Sorin, Solemn Visitor
+1: Until your next turn, creatures you control get +1/+0 and gain lifelink.
−2: Create a 2/2 black Vampire creature token with flying.
−6: You get an emblem with "At the beginning of each opponent's upkeep, that player sacrifices a creature."
9/20/2014 Only creatures you control as the first ability resolves will get the bonuses. Creatures you come to control after that happens will not.
9/20/2014 When the emblem’s ability resolves, if the player controls no creatures, the player won’t sacrifice anything.