Abel is 02. Cain 01 killed 04 i think because she changed abel to good side. remember puppet master said that Abel was Contra Mandu(sp?) which means against the world (according to mahou subs). In one of episodes i think episode 2 (witch hunt) Cain said holding 04 by hair that he removed only obsticle, which also implies that seth wasn't tottaly against their plans or she was too weak to oppose them. I think Abel has started Armagidonand then Cain joined him.