That is what I say I mean there is no logic to made em influenced by bleed, I mean from where would they supposed to bleed???
Technically speaking, it's a fantasy world so they can do whatever they want. For instance, all you'd have to do (simple showcase) is write lore that, like vampires, undead are sustained by blood or life, maybe they have grotesque sacs attached to them and they go collect blood, ect, ect. Obviously that would go against current lore but you could also argue a new breed of undead with story context, blah blah blah. My point is that anything possible and the only real consideration is allowing it to make internal sense via good writing.
Also, blood is made in bone marrow. Irreverent, but wanted to point that out.
