Xiuu was emprisoned for being a traitor.

The elves had emprisoned humans because humans' ancestors had attacked the elves' ancestors. The current elf prince decided to take revenge. And he also decided to emprisone every elves that would think that humans deserved to be free. Xiuu was sitting in his cage, outside, exposed to the freezing night and the cold rain. Xiuu was looking down, thinking, when the door opened and a human got thrown in, and he looked at his new cellmate.