Mithale, Vain Queen

Whenever an elf you control dies, add {r} to your mana pool.
As long as you have 6 or more {r} in your mana pool that was produced by non-land sources, Mithale gets +6/+6, gains first strike and trample, and is a demon in addition to her other types.
"I will have the power to destroy kingdoms. A shame you will not be around to witness it."