Recently I saw a fantasy race that has a pocket realm that grows alongside them and accessed through an item they are attuned to. From what I know GURPS is known to be 'The TTRPG that has rules for creating everything' but I can't seem to find an advantage that would accomplish such a thing beyond maybe jumper. The thing I have in mind is basically a realm that grows as the character accrues points and can only be entered by the character or their partner and has a fixed entry point. Is there such an advantage or limitations to jumper that could accomplish this?
Are there any advantages that grant you a pocket dimension
gurps-4e
Best Answer
This was comprehensively written up by Christopher R. Rice in his article "Lord of Your Own Domain" in Pyramid #3/63 Infinite Worlds II.
It uses an additional form of Jumper, so you were on the right lines, with a large number of special enhancements and limitations for customising your pocket universe. There are also modifiers for the Control, Create, and Warp advantages, notes on particularly applicable disadvantages, a new Power, "Domain", psionics versions of these abilities, campaign guidance, adventure seeds, and a sample NPC.