Velpser
Velpser is, like Mara, a demon. He is linked with Belldandy by the Doublet System. In chapter 99 of the manga series, he says that he and Belldandy are linked, so if one dies, then the other will die as well (such is the way the Doublet system works). He is same age as Belldandy, but he changed his form as a young boy to come to earth. The reason why he did this was because he wanted to make sure Belldandy upholds a promise she made with him, which was to never forget about him. When she remembered his name, he went back to Nifelheim, but he comes back as a little harmless (? We shall see...) black kitty in Chapter 101 (Which Beldandy names Velsper). Looks like another resident in Morisato residence!Oh My Goddess is property of Fujishima Kousuke, and in the US is distributed by Animeigo (the anime), and Dark Horse (the manga).
