Nightmyste is a rarely seen DMFA character. Merlitz described him as "Arch druid and illusionist" - who apparently liked to use illusions to cheat at cards.
Nightmyste first appeared in strip 52. However after an incident regarding a human, Merlitz was kicked out of his old adventuring team. Nightmyste ran into "Merlitz" (it was actually Abel in disguise) again at the Lost Lake Inn , while investigating for some Cubi. The party left the inn at "Merlitz"'s request, though they briefly considered attacking the Cubi they found.
Nightmyste and the others of Merlitz's old adventuring party are based on real person's characters, which is something Amber has been trying to avoid , so it is they will likely remain bit-characters.