Welcome to the Worth the Candle Wiki[]
A teenager struggling after the death of his best friend finds himself in a fantasy world - one which seems to be an amalgamation of every Dungeons and Dragons campaign they ever played together. Now he's stuck trying to find the answers to why he's there and what this world is trying to say. The most terrifying answer might be that this world is an expression of the person he was back on Earth.
Worth the Candle, a webnovel written by cthulhuraejepsen.
Synopsis:
From the age of nine, Juniper Smith began filling notebooks with his worlds, at first places of fantastical imagination, but later with each as an expression of some theme or idea that momentarily grabbed his interest. Over the course of eight years, he shared these worlds with his friends through twice-weekly sessions of tabletop gaming. Now at the age of seventeen, he finds himself in Aerb, a world that appears to be an amalgam of those many notebooks, stuck trying to find the answers to why he's there and what this world is trying to say. The most terrifying answer might be that this world is an expression of the person he was back on Earth.
You can find the story on Archive of Our Own.