The Taming of the Stolen Lands
Tartuk is a kobold with bright purple scales.Tartuk is a gnome who tried to double cross his village but failed when the ogres attacking it killed him before he could surrender to them and offer to help them destroy the village. Thinking he had heroically sacrificed himself, the village used a scroll of reincarnate to bring him back from the dead. Unfortunately for Tartuk, he came back as a kobold with bright purple scales. Enraged at this, he fled into the woods, joined a local tribe of kobolds, and manipulated them into attacking his former village. Both side mutually destroyed each other. Since then, he had drifted through several River Kingdoms, periodically haunting towns and murdering gnomes. He also works his way into kobold tribes, taking them over from within. So far, he has destroyed two tribes and is working on destroying the Sootscale tribe.
Tartuk uses a statue of a devil that he calls Old Sharptooth to keep the kobolds in line. He has convinced them that if they do not obey his command the statue will curse them. ‘Bad kobolds’ are sacrificed to please the ‘god’ during his sermons, which he enhances with his illusion magic.
See p. 40–41 for how he reacts when the PCs arrive in the cave.