other vampires you control get +1/+1.
when edgar, charmed groom dies, return it to the battlefield transformed under its owner's control.
edgar markov's coffin
at the beginning of your upkeep, create a 1/1 white and black vampire creature token with lifelink and put a bloodline counter on edgar markov's coffin. then if there are three or more bloodline counters in it, remove those counters and transform it.