Sakuya Kira039s drugdealing best friend killed when Setsuna under Alexiel039s control is tricked by Rosiel. When he dies EnraOu enlists his help to test and preferably kill the Messiah. While he and Setsuna do not get along initially they become friends and defeat EnraOu. He acts as a guide to Setsuna while he is in Hades and dies in order for them to defeat EnraOu. He is then revived and given a new body by Uriel going on to help Setsuna in the remaining story arcs. Initially a source of comic relief Yue slowly becomes a tragic character as his new body begins to decay particularly after being grievously hurt by Lucifer.