Lucifer, Bringer of Doom

When Lucifer, Bringer of Doom enters the battlefield put two +1/+1 for each creature you control. Whenever another creature enters the battlefield under your control, put two +1/+1 counters on Lucifer, Bringer of Doom. Whenever a creature you controlled leaves the battlefield, remove two +1/+1 counters from Lucifer, Bringer of Doom. Creatures you control get +1/+1 for each +1/+1 counter on Lucifer, Bringer of Doom divided by two, rounded up.