i dont know about the weaopns but i do know one thing no matter what armor you where one
hit from fatalis will pretty much kill you

as far as weapons go all i can say is try out your most powerfull weapons on him and see
what works best

I haven't killed him yet, but I'm about to try the black cannon (heavy) on him. Bring a
all the materials you have to make crag, clust, and Peirce shots. Maybe a few more. Anyway
just don't stand in front of him and just keep poundin him with ammo.