Vassilis's Arcane Sanctuary

This spell creates a permanent extradimensional sanctuary. When you first cast it using a 7th-level spell slot, you touch a closed door and expend 2,500 gp of diamond dust to create the sanctuary: a space of up to 50 contiguous 10-foot cubes, configurable into rooms and levels. The space is unfurnished, with plain stone or wood surfaces (your choice). This initial door remains connected for 24 hours.

The sanctuary has a single entrance door. All connected doors lead to this entrance door, and from there, you can exit to any connected door.

On subsequent castings, you can link a closed door to the sanctuary. Each casting lets you set access conditions—like a key, password, or list of permitted individuals—that apply to the sanctuary as a whole and can be redefined each time. Linked doors appear normal unless viewed with detect magic or similar effects.

Temporary Connections: Casting the spell with a 7th-level slot or as a ritual creates a temporary connection lasting 24 hours. Only one temporary connection can exist at a time; making a new one severs the old one. One hour before it expires, you feel a growing sense of urgency until you exit or dismiss it. Temporary connections last until the door is destroyed or dispelled (as a 7th-level spell).

Permanent Connections: Using an 8th-level slot and 250 gp of diamond dust, you can create a permanent connection. You may have up to three permanent doors; adding a fourth requires severing an existing one. Permanent connections last until the door is destroyed or dispelled (as an 8th-level spell).

Exiting the Sanctuary: Inside, you exit by opening the entrance door and choosing a connected door, if you meet the access conditions. If a connected door is destroyed or severed, you cannot exit through it.

Persistence: The sanctuary endures indefinitely, even if all connections are lost. You can restore access by linking a new door.

Ritual Casting: As a ritual, this spell can create the initial sanctuary or temporary doors, but not permanent ones.