Darth Nihilus, Lord of Hunger

Wither (This creature deals damage to creatures in the form of -1/-1 counters.)
At the beginning of your upkeep, put a -1/-1 counter on each creature on the battlefield.
Darth Nihilus gets +1/+1 for each creature with a -1/-1 counter.
"All life... exists to feed your power, and my life... my life is yours."