Spell created by Selxis the War Mage known to his party as Sloth.

When cast this spell conjures a doorway within 5 ft of the castor, into a tower that must be physically built and warded everyday over a years time. The doorway serves as a teleportation circle and is magically connected to a door set into the middle room of the tower and serves as the core of the magic structure. The tower may have up to a maximum of 10 rooms aside from a kitchen, restroom, dinning hall, laboratory, and study for a total of 15 rooms. The tower must include those 5 rooms as they complete the magic circle of the original spell. Other than the first floor the tower may be completed as desired by the castor. Discuss with your DM to roll for tower defences based on spells known to the castor at the time of building and warding the physical tower.

If cast at level 20 the castor can link to a tower with 20 total rooms.