Monsters populate every battle room the heroes must clear in order to reach their final foe, the dreaded Catacomb Lord.

During the Battle Phase, the Overseer controls all the monsters on the playmat. Like the heroes, each monster takes one turn per round of the Battle Phase.

There are five monster families: Dungeon (green), Infernal (orange), Mythological (blue), Undead (gray) and Vermin (brown). Each Monster card has the following information:

Health: Indicates how much health a monster has. Monsters have between one and four health points. Monsters with four points of health have a health track on their cards.

Reward: Shows how many gold coins a hero collects in the Resolution Phase for destroying this monster.

Monster Metre: Shows what family a monster belongs to (by the colour) and what level it is (by how many circles are filled in on the metre). Level 1 monsters are the weakest and Level 4 are the strongest.

Defensive Properties: Some monsters have defensive properties.

Shot Sequences: Summarizes what shots the Overseer can perform with this monster.