He's aware of the blood trade, which he always worries can turn ugly like a black market if people act in bad faith, and of blood donations. He'd have done a few himself for the purpose of saving lives, but, as with anything connected to his body, he'd always worried his Quirk might make things weird.

Logically he knows it shouldn't; One For All can only be passed on by his will. But magic is something he knows next to nothing about, since he can't do it himself. Sometimes the magic of this world doesn't play nicely with the magic a Sleeper has from their own, and he has no idea if it treats a Quirk as such.

"And the... method you copied from those people, the zealots? Are you talking about the negation of our powers?"