Other Vampires you control get +1/+1.
When Edgar, Charmed Groom dies, return it to the battlefield transformed under its owner's control.
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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.

NOTE: Stock image, not actual card.