Nekros, Corpse Sanctuary

When Nekros, Corpse Sanctuary enters the battlefield, target player loses 1 life.
{t}: Add one mana of any color among Zombie permanents you control to your mana pool. Use this mana only to cast Zombie spells.
During each player's turn, whenever one or more Zombie permanents enter the battlefield, target
player loses 1 life until end of turn.