The Castle Perilous series is a fantasy adventure series of novels written by John DeChancie, starting with the eponymous Castle Perilous in 1988.
144,000 doors (or "aspects") of the Castle each lead to other parallel universes.
Those who find themselves at the Castle often stay to become Guests, and (to their surprise) develop a magical power of their own.
This gift is apparently random, and can range from a minor telekinesis limited to lifting pencils to super-enhanced senses to teleportation to full conjuration of matter.
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