User blog comment:Schiffy/BG9: Man, Machine, or Something Else Entirely?/@comment-4957813-20130918021438/@comment-11051098-20130918221921

That would be too ridiculous, I think. My theory is that BG9 is a male humanoid cyborg of some kind. The countless tentacles could be a form of arms, or he could have actual arms, and the tentacles could be a sort of "extra function" and maybe his preferred limbs.

Although, in the panel where he takes out the huge chain-gun spirit weapon, it looks like the tentacles are the only form of arms he has. And they're apparently both fast and very durable, easily penetrating solid buildings.