What would an Heir of Blood be able to do ability wise? I mean like how John was able to control wind and turn it into weapons/literally turn into the wind, but as a Blood player.

I feel they’d be good pacifiers. Changing Blood Selflessly seems like someone who’d try to keep the group together- But if you’re talking about raw powers like John’s? Blood Bending, all the way, and possibly becoming a Blood Puddle themselves. That’s always fun.