"My own blood is just fine," Duke said. "You know, other than trying generally to keep it inside my body where it belongs."

He wouldn't start leaking troubles every time he bled for a little while yet, after all.

He focused in close on his diagramming, not quite up to looking at her while he tried to explain his trouble. "It's, uh. I guess it kind of works like a drug on me? When I touch the blood of people with magic or powers or whatever. Like . . . a quick blast of PCP. I get all extra strong and aggressive and, uh. Vaguely homicidal." More than vaguely. But he tried his best to curb that. "Or if it's Lucifer apparently I just pass out."