This is the first book in the Gorp the Goblin fantasy series by Jon Ray.
Gorp the goblin is fleeing his lands in search of better employment. With only a cloth map to guide him, he sets out across the sea to secure work at Ye Olde Dungeon working for the sinister Dungeon Overlord Jamalin Spellslinger. Once there, along with a group of misfit monsters, Gorp is hired on as a janitor to clean up the messes left behind by the horde of fortune, glory, and treasure seeking adventurers. But all is not well within the dungeon as the Red Dragon has ideas and an agenda of his own.