Kegan’s power and skill places him as one of the strongest fighters that the group had ever faced. His strength stems from his mind instead of his body. Like both Jack and Lilium, he was awakened by an illithid under Sarthel. According to Jack, the helmet Kegan wears limits his powers.
Kegan decided to help train Lilium to better control her powers. He realized though that she was more like Jack then she was like him, so he reluctantly allowed Jack to join in on the training.
With his mask on Kegan seems distracted and prone to uttering as few as words as possible in a conversation. Without his mask he seems more talkative and yet more guarded. In both forms he seems rather polite and willing to do good.