The Red Keep, Aegon's Bastion

The Red Keep, Aegon's Bastion enters the battlefield tapped.
{t}: Add {r} or {b} to your mana pool.
Sacrifice a creature, {t}: Create two colorless
artifact tokens named Gold with "Sacrifice this artifact: Add one mana of any color to your mana
pool."
Only the blood of the dragon would ever know the
secrets of the fortress the Dragonlords had built.