Kayn is a 20 year old man, younger and more naive than his master Zed. He's one to question decisions and argue back, but he trusts Zed whole heartedly. Zed saved him as a child and now trusts him to lead the Order of Shadow in the future. For this role, you can go for impersonation or interpretation of the role. No direction is going to be weighed more than the other. Don't feel the need to have a spot on impression just because there's an existing version of this character's voice.

All of these lines are relatively the same. Kayn is being snarky, suggesting ideas and his usual Kayn self. As with Shen and Zed, you can do a voice line or two from the game if you like.