Fortress Mimicry

User with this ability either is or can transform into an fortress, fortified structure with ability to store/create people, weapons, vehicles, and defenses from inside their body and release them at full size. User may appear physically as a fortress, become one when they use their powers or keep their normal form constantly.
On the most basic level, users internal anatomy remarkably spacious and capable of having other beings/creatures/technology/structures stay/exist inside them for extended time while supplying their visitors with habitable environment.
On the more advanced level user can create/summon beings/creatures/technology/structures inside them and deploy them as needed. If user is of relatively human size, their troops will transform into full-sized form after exiting their host.