Like all pure-blood nobles, he possesses red eyes and an attractive face. Initially, he has a rather slim build and has short, wavy blonde hair. However, at some point he seemingly enters puberty, and becomes taller (almost as tall as Karias), his body more manly, and becomes more handsome. Recently, he has started to wear masks to battle, a trademark of his brother and father.
At first, Rael displays a haughty, vile, immature and arbitrary nature accompanied with a tremendous loathing for humans (it's speculated that the Union's first attack on Lukedonia centuries ago, which caused the demise of Regis' and Seira's fathers, has something to do with Rael's hatred of humans). His bias is so great that he refused to cooperate with his human allies, threatening to kill them after the battle was over.
Rael was also overconfident and thought very highly of his abilities. He continuously underestimated the enemies even after losing to them. He has deep pride in being a Noble and could not tolerate anyone thinking they are above him.
Rael is also stubborn by nature, pursuing his love for Seira even after she had already rejected him many times. He later learns to accept the one-sidedness of his feelings. Still, he tends to act possessive sometimes, showing hatred toward those close to her. As the story progresses, his possessiveness of Seira and his hatred of humans slowly lessened as he even came to care for their safety.
Despite his cold exterior, Rael genuinely cared for some people. He displayed jealousy towards his older brother, the clan leader, in earlier times. However, he harbors deep respect, love and care for him. During Rajak's battle with Frankenstein, Rael immediately offers his own soul weapon, Grandia, to the wounded Rajak so that Rajak's soul weapon, Kartas, can become whole. However, Rajak adamantly refuses because their father gave it to Rael as a present and encourages him not to give it up easily. After that, Rael comes to accept his brother as Clan Leader.
He also acts like somewhat of a brother figure to Regis, bickering with him, yet always reluctantly helping him. This care extends to the other members of RK-5 as well.
Rael shows great loyalty to Lukedonia. Despite the fact that he was almost dying, he refused Ignes' offer to side with the Union, saying that he would rather die than betray his race.
Rajak's death changes Rael. He is shocked, shattered and furious after realizing that his brother is no longer alive. With the help and guidance of Frankenstein and Karias, he gets over the trauma, matures and embraces the role of clan leader, significantly honing his fighting skills to honor Rajak someday.
Rael Kertia (Kor. 라엘 케르티아) is the younger brother of Rajak and a pureblood from the Kertia clan. It is known that he has lived for at least 500 years. 10 years before the present time, Rael proposed to Seira and was rejected. He couldn't contain his anger and destroyed everything around him. Rajak caught him in the end sentenced him to 10 years of confinement.
After 10 years of imprisonment he comes back and enters the human world to take Seira to their Lord as per order. During the fight between Frankenstein and him, it is revealed that Rael's father had secretly bequeathed him with a part of his soul weapon, realizing his younger son's dejection. He has managed to hide it from everyone, including his brother (even though Rajak already knew the secret all along). However, Rajak has seen Rael using the weapon while fighting against M-21, Tao and Takeo in Lukedonia. Later, after the battle between Lord and Rai was settled, Rael was said to be missing. According to the Clan Leaders, Rael left Lukedonia to avoid shame. He was later invited to stay at the RK residence along with his brother after a battle against multiple Union Elders.
After 10 years of confinement, Rael walks free and greets his brother outside the Lord's hall after a clan leaders' meeting. He explains that he wanted to pay respects to the Lord and asks what the meeting was about. Rajak reprimands Rael for calling him "hyung" now that he is the Kertia Clan leader. Rael responds by saying that calling him "clan leader" makes it seem they are distant as they are brothers. He then asks if Rajak is going back to the castle to which Rajak immediately replies that he is leaving on a mission for the Lord. Rael wonders what is so important that a clan leader should be sent and Rajak tells him that it is to bring Seira back to Lukedonia. At her name, Rael lights up and volunteers to take on the mission, persuading his brother to assign him, to save his brother's clan leader's dignity. He further says that not just anyone should be assigned the mission and it will look better as he is the clan leader's brother. His brother finally gives in on the condition that Rael should not cause any problems again. Rael expresses his acceptance of the condition with a smile.
Rael proceeds to carry out the mission and comes to Ye Ran by following Seira's scent. He draws every nobles' attention by starting using mind control on the school. He meets the three modified humans (Tao, Takeo and M-21) who act as the school's special security division and has a brief fight with them before Seira and Regis come out. He proposes to Seira once again after his blunder 10 years ago, but she still rejects him like she did before. He offers her time to think about his proposal but Seira immediately seeks him later that night.
With Regis tagging along, Seira goes to Rael to reject his offer and upon arriving, Regis and Rael criticize each other. Frankenstein arrives just in time to save Regis from Rael's sneak attack. A brief altercation with Frankenstein follows. However, Rael reveals that Seira has been summoned back to Lukedonia by The Lord. She quietly and promptly obeys the order and returns with him, leaving Regis with Frankenstein.
Rael fulfills the mission that his brother and clan leader assigned him and Rajak brings Seira to report to the Lord. The Lord asks Seira about Gejutel's report but upon receiving no answer, she sends Seira away and calls a clan leaders' meeting. Rael is allowed to the meeting although no one but a Gaju should be allowed to enter where he witnesses Seira's defiance in answering the Lord's queries. The Lord asks Rael to recount the conflict that he reported. Rael states that he engaged in battle with unknown people while carrying out his mission. Rael confirms that there seems to be a connection between them and the human-made organization because three of his opponents were enhanced humans. He adds that he could not identify the fourth person (Frankenstein) but that that there is surely a personal connection between the modified humans and the fourth person, which suggests a connection between this fourth person to the human-made organization. Rael reveals that Seira and Regis may know his identity as the two young nobles were staying with those people. This last statement makes the Lord and the rest of the clan leaders bewildered and the Lord demands the truth from Seira. Gejutel covers for the young clan leader and the Lord accuses him of treachery. Rael witnesses all this as he continues to kneel down quietly beside Seira.
After the meeting, Rael and his brother provide their company to the Lord who visits Gejutel's holding cell to question Gejutel again. When the Lord has gone, Rael blames Gejutel for Seira's predicament and tells him to free Seira from the Landegre clan so that Rael could take care of her instead. Rajak scolds Rael, saying that it is not the right place to make such comments. After Rajak apologizes to Gejutel, Rael keeps his behavior in check. Rael describes the person he could not identify for Gejutel, telling him that the blonde person is certainly strong but not enough for Gejutel to be concerned about. The old clan leader laughs loudly at the last statement, making Rael irritated. Gejutel implies that Rael would not be able to survive if Frankenstein used his full power.
While Rael walks through a corridor while pondering Gejutel's allusion, he sees nobles scurrying and asks them about what the commotion is all about. One of them replies that there is a report of intruders in the Forbidden Region. Rael returns to Gejutel's holding cell and relays the information about the intruders to his clan leader and talks directly to Gejutel when he says that he has heard a rumor that Regis is among the intruders.
Later on, Rael visits Seira in her holding cell and passes on the information that Regis is causing ruckus in the forbidden area and that Gejutel has been sentenced to forced eternal sleep. Rael leaves, believing that the information has caused Seira a great shock and later appears before the clan leaders Ludis, Rozaria, and Karias who were discussing the fate of Gejutel and Regis before he interrupted their conversation. As an apology for having eavesdropped on their conversation, he offers to capture Regis for them.
Rael runs to the forbidden area and intercepts Regis and M-21. Regis escapes as M-21 faces him in battle, with Tao and Takeo in support. Rael wins over the rest of the RK-4 using Grandia but fails to hide his soul weapon from his brother who suddenly arrives. Rajak tells him to hold his explanation for later as he needs to take care of the enemy. Unable to comprehend, Rael states that there really is no need to fight but when he turns around, Frankenstein and Rai has appeared. Rael identifies Frankenstein to Rajak as the one whom he has fought and tells his brother that he'll take care of Frankenstein. While moving torwards the enemy, he senses an intimidating feeling from Rai and momentarily becomes taken aback. Rai leaves Frankenstein to deal with the Kertia clan leader and steps forward. Rajak blocks him but Rai's speed overwhelms Rajak. Rael suddenly shouts in pain as Frankenstein's spears pierce through his body and Frankenstein reveals that it was just a consequence for Rael who attacked him from behind. Rajak rushes to Rael's side and tells him to stay back as he takes over the battle. Rajak adds that Rael's inability to comprehend the opponent's power proves Rael's insufficient power to face Frankenstein. Rael still continues to underestimate Frankenstein until Rajak takes out his soul weapon.
Rael quietly watches as the fight between his brother and Frankenstein goes on. When Rajak hid his presence, he confidently believes that Frankenstein's death is imminent and watched happily as Frankenstein suffers from his brother's attacks. To Rael's surprise, Frankenstein successfully reveals his brother's presence. Rael continues to be engrossed in the battle until he notices the Tao, Takeo and M-21 also watching the fight. He attempts to attack them but Frankenstein blocks him and receives a severe blow from Rajak's attack. Rajak takes Rael and scolds him for the way he just acted and Rajak apologizes to Frankenstein before wounding himself, to Rael's disbelief. Rajak tells Rael that as the clan leader, he should take responsibility for Rael's underhanded tactics because he doesn't approve of such and doesn't want to disgrace their family. Rajak reminds a stunned Rael that although the Kertia clan specializes in stealth, it does not mean that they should resort to foul play. The fight resumes and Rajak slowly loses ground. Rael, being witness to this, wonders whether Rajak is losing because of an incomplete soul weapon. He thinks about relinquishing the ownership of Grandia to complete his brother's soul weapon.
Rael suddenly appears in Ye Ran while the RK-4 are fighting against the assassination squad members. He overhears Yuri's remark about Seira, annoyed that a human toy will speak her name. His timely arrival saves M-21, Regis and Takeo, who were weakened by poison, and he starts fighting the opponents though maintaining antagonism with the RK. Tao speaks to him through Regis' communication device and tells him things to fuel Rael's protectiveness over Seira. Now enraged, Rael declares that he will kill all of them. He takes out his soul weapon and easily lands attacks on his enemies. He then asks Yuri to identify himself in the group so Tao describes Yuri for him and Rael uses his doppelgänger illusions to confuse them. He moves to kill Kalvin but the boy threatens to break the antidote he holds. Rael pauses for a moment when Regis pleads to him to stop because they needed that antidote and Tao explains that the children were poisoned, children who are friends with "him" and Seira. Yuri and Mark take advantage of this opening to attack him and escape. Rael becomes irritated and kills Kalvin, apparently not caring for the antidote. Regis, M-21 and Takeo stare in despair as they think about the destroyed antidote but Rael holds up his hand and shows the small vial to them. He tells Regis not to plead to him again.
The Earnest Wish
Rael, Tao, Takeo, M-21 and Regis are back at Frankenstein's house with the children. He complains to Tao how he made him carry the children but Tao explains to him that he's the fastest and they're running out of time. Tao adds that Seira will feel sad if the children were harmed. Regis agrees with this and says that Seira will be pleased to hear what Rael did. Rael stops complaining and remains silent.
Rael arrives at the battlefield where Ignes and her anti-clan leader weapons have been cornering Seira. His presence is welcomed by Ignes, who assumes he is the same as her, having no soul weapon. Rael gets an offer to join her but rejects it immediately, further shocking Ignes with revealing his soul weapon to fight her. As Rael engages in a battle with Ignes, Seira struggles to keep up with the three weapons and finally is brought down with an attack from Ignes. Rael watches helplessly as Ignes kidnaps Seira after aiming a parting blast for him. He is however, saved from the attack by Regis and the two of them decide to follow Ignes to rescue Seira after a little bickering.
Rael and Regis arrive at Roctis' Island after days of swimming to cross the ocean; Rael having left traces for his brother to follow. The two young nobles set to scout the island without the knowledge that Ignes has intentionally let them follow her. Soon they are greeted by the 9th Elder and a short fight decides their capture. Both Rael and Regis become the experimental subjects to Ignes and end up in her lab alongside Seira until Rai arrives to rescue all of them.
After the battles in Roctis' Island conclude, everyone is taken back home where they get treated of their wounds. Rael is thrilled to hear that the Noblesse rescued them but gets rebuked by Regis who reminds him how the Noblesse exhausts his life force everytime he uses his powers.
The latter few days, Rai's declining health becomes the chief concern of the entire household until the noble Lord visits the human world and stabs Rai to his revival.
As Frankenstein's household resume their normal activities (attending class, duties at school etc.), Rael remains in the house with as the two superior nobles (the Lord and Gejutel) pass their time idly. Gejutel's attempt at brewing tea for their Lord turns into a mass disaster in the kitchen and Gejutel leaves it to Rael to fix the place without leaving a trace of the destruction. Although reluctant at first, Rael agrees to the task immediately at the mention of Frankenstein and his possible crazy reaction if ever he finds out what happened. As the dignitaries leave, Rael stands in the mess and one move to start cleaning unfortunately leads to a leakage in the plumbing system. He frantically calls out his soul weapon to deal the situation, albeit causing further damage to the place.
Rael finally calls Tao for help and the kitchen is fixed. Later Rael, along with Karias, receives a proposal from the RK team to join them. At first, he exclaims it is an insolence asking him, a pureblood noble, to join a modified human team but upon learning that the 'RK' actually stands for 'Raizel Knights' and also Seira is in the team, he realizes his mistake.
During the training session of the guard trio in Frankenstein's Island, Regis returns home and asks to train with Rajak. Rael, who is present during the request, offers to train him instead so as not to allow Regis to interefere with Rajak's duties as a clan leader. However, Rael's training drives Regis to physical exhaustion and Regis gets bedridden. Rael, then, remains the only one to take care of the household chores and is also obliged to look after the children when they come to visit Regis. He volunteers to accompany Regis, realizing the latter is far from recovery from the training, in escorting the children home. On their way, Rael reflects upon the fact that his decision to join Regis was worthwhile when suddenly he receives a call from Tao. He is warned of enemy's presence but before Tao could tell him the enemy's location, communication cuts off. The entire area suffers a blackout. Rael tells Regis to take the children home while he decides to divert the enemies.
While on the way to meet the enemies, Rael reflects upon his decision to reveal himself as it is not the specialty of the Kertia clan. After putting enough distance between him and the children, he lures the enemies to him until he finally senses that there are two enemies. Rael remarks that he didn't expect them to catch up so soon and ponders whether he should get ready for a confrontation but realizes his location - the area is populated by humans. He decides to lure the enemies elsewhere where humans will not get involved and tries to convince himself afterwards that his decision is only because humans will get in his way. However, Grui and Gaitan still catches up to him in a populated area. Rael succeeds in luring them away into a deserted island offshore.
Rael battles against Grui, who insisted on fighting the noble alone. Provoked by Grui, he summons Grandia which makes the opponents believe that he is a family leader. Grui transforms and they continue fighting but Rael realizes that his attacks are not working. Just as the werewolf announces his disappointment over his opponent, Regis makes an ambush attack which allows Rael to slash a distracted Grui on the face. Working together, Regis and Rael continue battling with Grui. The werewolf, enraged that he got a wound just because of some kids, decides to kill off both and resumes the fight. However, the nobles' teamwork proves ineffective and Regis soon gets hit by Grui and sent to the ground. Rael takes over the fight to stop Grui from finishing Regis.
Grui overpowers Rael on the fight but before the werewolf could finish him off, Regis summons his clan's soul weapon, surprising Rael. With Regis' newfound power and their teamwork, they eventually fight on par with Grui. Before Rael and Regis could eliminate their opponent, Gaitan steps up to battle. Tao, Takeo and M-21 also arrive at the battle scene to relieve Regis and Rael from fighting.
Rael believes that the trio are no match for the werewolves and tries to convince the trio to flee while he and Regis try to hold off the opponents. They refuse him so Rael stays back to watch with Regis as the fight progresses. Gaitan soon gets the upperhand against the trio. Since they're all in bad condition, Rael thinks that he should let at least one of his comrades escape. However, just as he decides that he has to act, Grui slashes him on his back. Rael falls to his knees while Grui attacks Regis. Rael jeers Grui for attacking, earning him another blow which sends him flying.
Rael falls victim to Grui's sudden attack and ends up severely wounded. Regis and his other comrades also fall one by one but Rai arrives just in time, enveloping Rael in a protective circle. The Noblesse faces their opponents. After the situation is cleared up, they are taken back to Frankenstein's residence to recover.
Back at Frankenstein's residence, Rael stays with Seira and Karias in the observation room of the laboratory where Frankenstein is currently monitoring the condition of the trio and Regis. Frankenstein warns Rael not to overexert himself but he insists to Frankenstein that he has fully recovered but a crack is heard when he tries to move rashly. Seira, who is beside him, becomes concerned and asks him if he is okay. Raels tries to shrug it off but Seira is unconvinced. Karias speaks up, asking about Regis' summoning of a soul weapon. Rael relays that what he saw wasn't an incomplete soul weapon like the Kertia brothers' but instead the complete Legasus. Rael thinks that Karias must find this hard to believe since even he could not believe it when he was right there to witness it. Karias hopes that Regis can wake up soon so they can ask him and Frankenstein answers that he will get well soon. Rael declares that he does not care and Frankenstein teases him by claiming he never said that Rael cared.
Rael then asks whether Karias knew about Takeo and Tao's upgraded powers which, he confesses, surprised him. He finds it unbelievable though that they cannot control those powers and proceeds to ask Frankenstein why he allowed them to acquire such dangerous powers that can consume them. Frankenstein remains silent, prompting Rael to become enraged. He shouts at the human but suddenly remembers his brothers words: Frankenstein is a human that their father has acknowledged. He must always watch how he speaks and acts around him. Therefore, Rael changes his demeanor to a calm and inquiring one, respectfully asking Frankenstein for the reason. The sudden change brings about stares from the three others with him but Frankenstein answers his question. Takeo and Tao wanted the power and Rael immediately thinks that this as expected of humans. Karias, however, explains that their reasons are not selfish and they only wanted the power so they can use it to protect their comrades. Rael remains silent at this while Frankenstein exits the lab.
Rael remembers another moment with his brother. In this particular memory, he asks his brother why he cares for and helps the humans train. Rajak is unclear as to why but he says that maybe it's because he can feel their earnestness. Rael points out that humans are earnest when they want something and Rajak understands what Rael is trying to point out but he tells his little brother that he also learns from the humans. Rael, puzzled, asks his brother what he can possibly learn from them. Rajak turns back with a smile and cryptically suggests that he would understand better if he sees and feels it himself rather than hear it from Rajak. Rael remembers how he told his brother that there would be nothing special to learn from them. As he continues to watch the unconscious humans, he wonders whether the desire to protect their comrades is the reason why the humans rapidly grew much stronger.
When Regis and the humans regain their consciousness, Rael accompanies Karias and Seira on visiting them. He jealously thinks it stupid of Regis when the younger jerks away from Seira's congratulatory pat on his head and that he should be thankful instead. Tao then enquires about Rael's condition and gives his thanks. Tao speaks up for his comrades to show how grateful they are for Rael's help in the recent fight as well as Karias and Rajak's help in training them. Rael cannot hide his concern anymore so he turns his back on them and tells them that they should not be content with their current state if they realize that his brother has spent his precious time for them. Rael rushes out as Karias and Seira agree that he is embarrassed.
Rael stands in the balcony, lost in thought. He thinks about how his comrades has gotten stronger since he met them and how Regis now has a soul weapon - a complete one. Their growth rate is astoundingly fast, he cannot help but think that they may catch up to him soon. As he agonizes about this fact, Karias appears behind him. As he leans on a wall, he asks Rael why he is all by himself. Rael tells him that there's no reason but Karias presses further, telling him that he looks blue for some reason. The Blerster clan leader then adds that Rajak will feel better now, a statement that piques Rael's interest. He asks Karias what he meant and receives the answer that it is because those guys (the humans) have gotten stronger. Rael confindently says that even though his older brother trained them, he is sure Rajak would not really feel better about them getting stronger. Karias asks him if he knows the reason why Rajak trained them. When the younger noble answers that it is because they were desperately trying hard, Karias reveals that there is another reason for it. Rajak was training them for Rael. It is because having strong comrades means less danger for Rael as long as he is in this world. Karias happily adds that that is also the reason why Rajak asked Karias to help train them too.
Rael is training in the practice chamber with Karias when he suddenly feels his heart ache. He clutches at his chest. Karias asks whether he pushed himself too hard and decides that they should stop training for the day. Rael insists that he can keep going but Karias tells him that it would still be best for him to take a break. He wants to keep going to show his brother how much he has improved through his training, unaware of what happened to Rajak.
Continuing with training, an unknown strength suddenly enhances the blow Rael aims at Karias who is taken aback by its impact. Rael wonders about the sudden power of his attack while Karias shakes his numb arm and inquires if he has been hiding his strength all along. Rael is alarmed and denies the accusation, stating that he also has no idea of what is happening. Karias ponders on it - judging by Rael's decreasing stamina due to continuous training, he should have been in no condition to pull out such a powerful attack. Such increase in power without the owner noticing is like a circumstance when someone has just awakened. Karias deduces it could be Rael's awakening. However, awakening is not possible if the soul weapon is not complete. Karias prompts Rael to bring out his soul weapon. Rael calls out Grandia and is shocked to see the daggers changed and surging with a new power. Karias acknowledges that Grandia has become complete. Karias suspects that something must have happened to Rajak and Rael is petrified with anxiety.
With a banging sound, Rael enters the living room where Frankenstein has summoned everyone for an urgent discussion. He sports a terrified look which hints at the others that something is amiss. Rael adresses Rai and states while stammering that his soul weapon has changed. Karias walks in and explains that Rael's soul weapon has become complete and his body has completely awakened. Rael surmises that his brother's soul weapon has united with his own but he still considers it impossible.
However, with this news, Frankenstein reveals that a short while ago, he has received information that might explain Rael's situation - Lukedonia is under attack. Rael sinks on his knees, bewildered at the foreboding presentiment that something bad has indeed happened to his brother. Frankenstein announces that he and his master will go to Lukedonia. Karias volunteers to join but Frankenstein turns him down since he would be more useful in this house. They cannot leave the injured to fend for themselves, should anything happen here and Seira alone might not suffice. Regis is turned down as well, since he is in no condition to fight and will only get in the way.
Finally, Rael volunteers to go but Frankenstein refuses his offer too, since his mental state isn't normal. Rael grits his teeth in rage, uttering that he wants revenge for his brother who has been forced to eternal sleep. This time, Frankenstein breaks off the calm demeanour and yells at Rael, scolding him for acting like a spoiled kid. He tells him to realize the reality - Rajak was strong and Rael, who has just awakened, can hardly make a difference while fighting against the enemies who killed Rajak. Rael sinks his head upon the realization.
After Frankenstein's return, he speaks with Rael who is still in the training room and comfirms to him what he fears - the death of his brother. He tells him how Rajak fought multiple opponents at the same time and it was thanks him that the invaders were delayed from the invasion. The delay saved Lukedonia by giving enough time for Rai and Frankenstein to reach Lukedonia. Rael's feelings lighten as he feels the pride of his brother's sacrifice for their homeland.
In a flashback, he remembers the love his brother felt for his homeland. Rajak reminds him to always think about how to use his power. Additionally, he tells Rael to remember that what is important for nobles like them should be how they live their lives and how they go into eternal sleep. Rael agrees that how they live is important but he tells his brother that he would take his time thinking about how he would enter eternal sleep since that would still be a long time away. Rajak coolly concedes, telling his younger brother to calmly think about it. Rael asks whether Rajak has thought about it, to which the latter answers an affirmation.
Back to the present, Rael realizes that his brother surely is contented with the way he entered eternal sleep: by defending his beloved Lukedonia. He mimics his brother's words, What's important is how they live and enter eternal sleep. Frankenstein agrees, remembering that Ragar also once told him that. He walks past Rael as he comments that Ragar and Rajak would be happy to see Rael understanding those words. Rael expresses his thanks to Frankenstein because his brother could meet the man that their father has missed so much.
After Frankenstein leaves, Seira enters. Rael receives words of comfort from Seira. He is then pulled into a hug as she explains that that is what's humans do to comfort a grieving friend. Seira tells him that it is his right to feel grief with a family member's disappearance. Rael breaks down.
Rael collects himself soon and enters the living room where he witnesses the heavy atmosphere from the RK members. He gives them a tirade about their reactions on his brother's death and the RK members are confused with his anger, of course they are depressed since Rajak was special to them too. Rael tells them not to sulk as his brother died a hero's death. He adds that his brother died standing up against enemies to defend Lukedonia and that his fate is not pitiful at all. Rajak met the eternal sleep that he wanted so he questions the RK members to about feeling sorry for him. He finally asks them to not show their depressed faces if they really thought of his brother as a special person. Rael then turns his back to walk away as he tells them to brace themselves because he will take over training the RK and he will not train them as lightly as Rajak did. Karias smirks as he lets out a comment about how Rael already seems like a family leader.
Rael arrives at the werewolf territory along with Karias just as Frankenstein is overpowered while battling a team of werewolf warriors. They each take on an opponent, in which Rael fights Krano.
Rael attacks Krano who recognises him as the Kertia clan leader but finds him lacking compared to the reputation he has heard of. The werewolf stabs Rael in the chest with his hand but Rael's body turns into a flurry of bats. Rael rushes at him from above, inflicting a gash on the dazed werewolf, and starts attacking at a blinding speed. He asks Krano whether he still finds him unimpressive.
With Rael's speed overwhelming him, Krano starts slashing blindly but regains his composure and punches Rael. The young clan leader crouches and blocks but is pushed back. Krano triumphantly declares that although his speed is commendable, it will be useless against him without realising that Rael has reappeared behind him. Rael increases his speed and overwhelms him with successive attacks.
A brief interval ensues. Krano admits that it was justified that the clan leaders were compared to them but states that the new power adopted by the warriors has given them an edge. He decides to use the power he gained from the physical modification technology and undergoes further transformation. Rael is shocked to witness his opponent's wounds heal completely and notes that his aura has become stronger. He covers his face as Krano slashes repeatedly and gets pushed backwards by a sudden kick. The noble rebounds and cuts Krano's arm but the injury is superficial. He crashes onto the ground after being punched and is nearly hit by a sonic howl Krano lets out. He gets worried since the warrior is now faster and stronger than him. But then, he remembers Rajak's words to never set limits for himself. The previous Kertia clan leader had advised him to always endeavour to surpass himself. Grandia blazes in a crimson flame by its wielder's resolution to conquer the odds. Rael envelops his nemesis in a blitz and slays him with a powerful attack, proclaiming that the clan leaders too have become stronger. Krano falls down with a large cross shaped scar on his chest and dies.
Rael gazes into the horizon in melancholy. Karias, who was battling Braang, stops by and tells him that Rajak would have been proud of him. Karias asks him to hold off Braang and runs away. Rael helps occupy Braang's attention until Karias can summon his ultimate skill and kill Braang.
Rajak Kertia: The Kertia brothers share genuine bond and respect for each other which has developed over time. At first, Rael apparently had a grudge against his older brother for inheriting the position of Kertia Clan Leader. Despite refusing to call him "Clan Leader", Rael respects his brother greatly and seems to seek his acknowledgement to some degree, often displaying happiness, surprise, and pride whenever Rajak praises him. Rael is shown to care deeply for Rajak and is concerned about his older brother's well-being and image as a Clan Leader. Rajak's death greatly influences Rael, making their bond stronger than ever. From then on, Rael always recalls and follows his brother's advice in times of trouble.
Seira J. Loyard: Rael has an infatuation with Seira and has publicly demanded Seira's hand in marriage several times, only to be rejected, as the feeling is not yet mutual. Regis previously suspected that Rael had wanted to marry Seira only to establish himself as a clan leader. However, the suspicion is later revoked in the flashback where Rael explains that it was just an excuse to pursue Seira. After Seira shows signs of affection towards Shinwoo, Rael becomes kind of confused about his feelings for her, maintaining that he is only "attracted" to her and holds no "special feelings". His actions and jealousy repeatedly contradict this though. Later, in volume 6, Rael's feelings for Seira is revealed to be indeed genuine.
Regis K. Landegre: Rael previously considered Regis more like a pest (the feeling was mutual) but with time, and the revelation that Rael genuinely likes Seira, they have grown to care for each other. Rael is protective of Regis during battles. Sometimes he shares his anxieties with Regis and even takes his advice into consideration.
Cadis Etrama di Raizel: Rael shows immense respect towards the Noblesse, and takes his word as law. He begins to get along with the trio after hearing that Rai has taken them under his protection. He looks up to Rai and once he even asks Rai for love advice.
The Trio: Rael treated the modified humans like scum when he first made his appearance. However, he was willing to ignore his personal hatred toward modified humans, Tao, Takeo, and M-21 in particular, after hearing that Rai had let them into his home and they are under his protection. Over time, being in the company of the trio through continuous troubles (caused by Union, traitors and werewolves), Rael comes to an understanding. He forms a sense of acceptance and regard for the trio. Sometimes, he even depends on them, for example, he calls for their help when Gejutel 'accidentally' destroys Frankenstein's kitchen.
As a adult pureblood noble, Rael possesses immense power, speed and combat skills. He is considered to be among the strongest of his clan. (Chapter 169) However, Rael has a weakness as he tends to become emotional in battle easily, resulting in mistakes. According to Frankenstein, Rael doesn't have much battle experience. He also has a tendency to underestimate opponents as he continuously believed Frankenstein to be weaker than him, even though the latter was instead stronger, proving that he lacks the strength to face opponents of such power as Frankenstein's (as told by his brother). Despite all this he is still a very powerful individual, able to take down Tao, Takeo and M-21 by himself. After fully awakening his powers, Rael becomes even more powerful. He was capable of defeating Krano, a powerful werewolf warrior and hold his own against Dorant, one of the most powerful werewolves who compares his power to that of his kinds true warriors.
Grandia: Grandia is Rael's soul weapon, consisting of a set of large and ornate daggers. He has kept his soul weapon a secret from his clan as it was a gift from his dying father (the previous Kertia clan leader), a partial soul weapon (created from half of his father's soul). Though the weapon only has half of his father's soul, Rael is still capable of doing immense damage and even Frankenstein admitted that it was "praiseworthy" despite the fact that it was still incomplete. It can be used to produce kinetic shockwaves that can create an upheaval of land, with an area of effect of two or three city blocks. Grandia seem to also vibrate at incredible speeds, allowing it to pulverize rock. Grandia can also cut over both a wide and miniscule area of effect. On a large scale, he can split small islands into quarters with ease. Also, Rael can use Grandia to slash at incredible speeds, many times faster than bullets. After the death of his brother, Rael has fully awakened his powers, thus completing his soul weapon, Grandia. The weapon has changed appearance with this occurrence. It now has a serrated edge, a streak of gold crosses its blade, and the handle has become more ornate.
Rael possesses incredible physical strength, able to pierce through metal, stone, bone, or flesh with ease, and he is strong enough to create shockwaves that can rip apart a forest or reduce skyscrapers to rubble. His physical durability is very high; despite being impaled by several of Frankenstein's dark aura blades, which are capable of killing modified humans without much effort, he remained alive and intact. Rael has also traded blows with the likes of Ignes, whose punches were able to destroy multiple skyscrapers or an entire city block. His most notable trait is his speed, being a member of the Kertia Clan. Rael has been shown to be fast enough to seemingly teleport to impale M-21 from behind, before he or his teammates could react. He is able to effortlessly dodge Tao's ensuing counterattack, then immediately return to his original position, all within a fraction of a second. He is shown to be fast enough to dodge almost all of Frankenstein's attacks without being injured (though his last attack did in fact damage him). He is also able to dodge bullets, even those fired from Takeo's powerful modified sniper rifle, and is capable of creating afterimages of himself to surprise his opponents. His speed is further increased after he reappears and saves RK-5. After fully awakening his powers, his speed increases dramatically. Despite being outmatched in power, Rael is still capable of outpacing Dorant in his enhanced form.
Doppleganger Illusions: Like his father and brother, Rael is also able to create multiple clones of himself to surround the enemy but his ability is limited to 3-4 illusions only. These illusions can be used for distraction, avoiding attacks or offensively attacking from different angles at once. After fully awakening his powers, he can create as many clones as his predecessors.
Mind Control: A common ability among the Nobles which Rael uses to incredible capacities. In one instance, he is shown to be able to freeze the thought process of every normal human within Ye Ran High School, which initially causes Regis to mistake his presence for that of a clan leader. With his mind control, he is also able to cause a large number of humans to completely evacuate an area which prevented them from getting harmed in his ensuing battle with Frankenstein.
As a Kertia Clan member, he can put a secret message of his clan on battlefield. It is a special secret Kertia method of communication. It can be read only by another Kertia clan member such as his brother and previous clan leader, Rajak.