The Final Void

Whenever you spend {c}, put a drain counter on
target permanent, it becomes colourless.
Whenever a colourless creature enters the
battlefield, if there are no coloured permanents
on the battlefield, draw a card.

"Our land was beaten, broken, and stripped of life.
You've taken everything from me, maybe ridding our
plane of the last of your kind shall grant me solace,
or at the very least, set me free."