Kay, so... ideas so far for potential Deadmen and Branches of Sin:

-Shrike: A deceptively innocent and vulnerable looking kid who is actually a hardcore sadomasochist who fights by intentionally letting his opponent spill his blood, then skewering them with spikes made from his own blood. A very trap-based fighter who indulges in causing pain (and who may or may not have a hidden submissive side). 
-Pheonix: A regenerator. Don't have much else worked out with this one yet besides their Branch of Sin being the child of the Wretched Egg's regenerative abilities.
-Thunderbird: A former assassin (probably Russian because yes) with a Branch of Sin related to electricity. Probably female, definitely very tall/large and and in charge.
-Mourning Doves/Finches: Two siblings who share a Branch of Sin that only works when they're together. Still unsure about the name because "Finch" doesn't sound as cool as "Mourning Dove", but pairs of finches may not necessarily be mates whereas Mourning Dove pairs are almost always mates and... ick.
-Cuckoo: A Deadman whose Branch of Sin only activates when their blood mingles with another person's, resulting in as of yet unclear (but certainly nasty) effects.

No idea which one of these I'm gonna use, to be honest.