If you have read Chapter 437 than you would see the flashback between Rajak and Karias in Lukedonia in which Rajak request Karias to take care of Rael as Karias is going to South Korea (at Rai's place). (Rajak ask Karias if he is going to Korea at Rai's place, and Karias says that Raskreia requested him to go...)
This is a big plot hole! Rajak went to Korea long before Karias. Raskreia sent Rajak to help Rai &co. after the death of 10th & 11th Elders. She chose Rajak on advise of Gejutel who said that Rajak was perfect choice as he is already out of Lukedonia (probably tracking Rael after his disappearance on season 3) and thus would easily reach Korea soon.. In fact both Rajak and Rael arrived at Franky's home in same time (after the death of Zarga and Urokai).
Karias went there long afterwards (during the kidnapping of Seira by Ignes). When Karias arrived in korea Rajak didn't even knew that Karias was sent here. Rajak asked Karias and he said that Raskreia begged him to take care of things. Rajak did went back Lukedonia but Karias was still in Korea. So there is no chance of this conversation happening between them.
No offense to authors but they forgot their own story! 😜