Serene Master

Whenever a creature attacks one of your opponents or a planeswalker an opponent controls, that creature gets +2/+0 until end of turn.

Death Grasp deals X damage to any target. You gain X life.

At the beginning of each end step, each player gains control of all nontoken permanents they own.

Players can't gain life. At the beginning of your upkeep, this enchantment deals 4 damage to you. At the beginning of your end step, target opponent chosen at random gains control of this enchantment.