Kayin was probaly the second best knight at the Silver Kingdom next to Tapion. But he didn't care. Him and Tapion were best friends and also sparring partners. He was very loyal to his queen and in love with her daughter, Jadis. Jadis felt the same towards him.

But, Shadow Queen was revived and the Princess went missing. After finding Lamika and believing she was the dark form of Jadis, he soon fell in love with her. Sadly, Lamika had other intentions.

It wasn't 'till Tapion disappeared when Kayin lost it. He joined the Dark Kingdom and changed his name to Keiin. (Same pronounciation.) Now, he simply doesn't respect women and takes what he wants when he wants. After Hollidai was born he became her servant. So now, he lives a pretty pathetic life.

(bg song: A Girl worth Fighting For from Disney's Mulan)