Under-Dungeon

Positioned beneath the Tourist Dungeon, and accessible via a locked door just preceding the final boss of that dungeon, the under-dungeon goes progressively deeper through the core of the island. All dungeons, basements, and sewers are interconnected. The cave system is complicated. A light spell is required. There are a few crates of ancient supplies stacked up. A skull here and there. At each level of depth, it gets darker and more awful. Lovecraftian horrors, TMNT NES game refs.

Residents of upper levels: Kobold