
What the hell? From the novel, Radan didn't get lost or escape but was lock up in Leshak's dangeon after Karum caught him. When Leshak came back from getting rid of the spy, he looked for Radan (which was seen in chap 27) but couldn't believe what happened and keep on denying that Radan was the Cryptic Assassin.
But Karum keep on insisting that Radan IS the cryptic assassin. His men believed Karum as Karum rarely lie especially he's the one who witness it (tho he did not witness how Radan melt the eyes of those 4 men).
Due to the pressure and disbelief, Leshak starts to feel his heart was crushing (this is effect of the curse btw) until he can't endure it anymore and he lost a part of himself which result to him being a ruthless and cold person (which can be seen in the latest chapter 28).
Also, before the start of the battle, Radan's brother, Raud, thought it was finally their opportunity to attack as they thought Leshak was dead which resulted to them being massacred by the said person they thought was dead. Raud flee tho, from the battle.
After the battle, Karum warned everyone that Leshak can't be left alone as he was not his usual self tho they did not understand Karum but later understand him after they arrived at Al Raksha.
Also, after the battle Leshak commanded everyone to eradicate Al Raksha from the land whether they want to join him or not. And they took Radan and was placed inside a cage. But before that, Leshak and Radan talk before they left, Leshak wants to confirm if Radan was really the cryptic assassin and Radan didn't deny it which makes Leshak very angry and his curse worsen.