A type of world created by a high-level demiurge AI, frequently using distributed godtech or clarketech artifacts.
In some cases the godlet will modify an existing planet into a fantasy world full of all sorts of mystic toys, isolate it from the rest of the universe, and then sit back and watch, interfering with the inhabitants occasionally through 'magic', mystic phenomenon, or through special priests whose brains are modified via ultra tech to receive the godlets communications, or any number of things. Or they make a world that is open to the galaxy, so that visitors and tourists can arrive and experience the wonders of the godlet's realm (sometimes to their peril, as some of these worlds contain dangerous artefacts). In some cases ultra tech devices taken a fantasy world cease to operate, at other times or from other worlds they work perfectly (and command astronomical prices on the galactic markets!), at still other times anyone seeking to plunder such a world - or even steal the tiniest item, is instantly killed by the local nano defense systems or some form of clarketech defense.