Rift Citadel (3.5e Equipment)
From D&D Wiki
The rift citadel is a small fortress capable of turning itself and everything in it into traveling energy once activated by the owner. When you gain ownership of a rift citadel you will be asked by a citadel spirit what type of denizens will be created in the citadels depths. The choices are demonic, savage, undead, lawful, and celestial as well as any others deemed appropriate by the dm.
In all their five creation forges that create creatures it takes two hours to create a medium creature, or 30 minutes per size category + 30 minutes base. The forges are directed by the owner using a orb in the central tower. The creatures created this way are fiercely loyal to the owner that created them.
The forge is fueled by giving it magic energy from magically infused objects or just using magic near or in the forge. Certain creatures also require special materials and creatures created in the forge are unequipped.
The primary workers in the citadel are the citadel spirits; they are invulnerable but cannot fight, and there are only two hundred regularly.
Rift citadels in addition to the guards and defenses built by the occupants usually have powerful magical means of defense.
To create a rift citadel requires the sacrifice of 50 willing creatures not created by another rift citadel, or 5000 unwilling and an offering of 3,500,000 gp to powerful magical forces, the equivalant magical strength of 5 lvl 16 wizards, the blessing of a God on the sacrifices if they are willing, or a fortress at least twice the size you want your citadel to be if unwilling.