ok, so ive been reading some of the posts around the beggining, and some of them are really lame and some of them are kinda cool.
but i dont think he will have like an actual weapon to use in a fight, but maybe like a crystal ball. something that "enhancess" his magical powers, but not necisarilly used as a physical attack weapon. maybe it could stay in the background so you would have to fight your way through zexion to get the the crystal ball and attack it.
and then i heard some where along time ago that he can like shape shift or something into other org members. if im wrong dont flame me, i dont want your crap.
but if thats true, maybe half the time in the fight he would be transformed into another org member. so like (what i have imagined in my head) he could be like himself, take one strike at close range at you with magic, and the transform into like larxene, strike you with the kunai, (mind you this is all close range) then transform into axel and attack you with a chakram... so on and so forth.
but i can also imagine hime with light beams like whats his name had. (enigmatic man) but the light beams could be all like dark lighted and black.