Obsidian Citadel of Stormheart

Obsidian Citadel of Stormheart enters the
battlefield tapped. When it does, a target
player on your team you loses 3 life.
{t} add {c} to your mana pool.
{b} Add {u} or {r} to your mana pool.
{1}{b Add{b}{b}{b} to your mana pool.
"How diabolical are the witches. To make a ring
of fortresses and power their darkness with the sun.: