He is Tethe'alla's Chosen One. His good looks, his title, and his smooth charm makes him irresistible with most women. Because of this, he can be a bit arrogant and egotistical at times. He doesn't take things too seriously, and thus has a laissez faire attitude towards his duties as the Chosen. Zelos also turns out to be a traitor. Yggdrasil promised to relieve him of his duties as the Chosen and pass the responsibility to his younger sister if he would help stop Llyod and Colette. But Zelos has learned to respect the group, and even like them (he seems to consider Lloyd a friend, amazing considering he wouldn't even talk to other guys at the beginning...) So, in the end, he and Kratos team up to save everyone and he rejoins the group. Although he hits on every woman he sees I think he has special feelings for Sheena...