Necromancer's Keep

Necromancer's castle comes into play tapped.
{t}Put a storage counter on Necromancer's Casle.
Remove any number of storage counters from Necromancer's Castle. Add one {b} to your mana pool for each storage counter removed this way.
"Deep within the darkened woods, past the devil's gaze. The Necromancer sends the damned, wandering from his maze." - Nezule's Chants