Nightwatch are ghostly enemies that are seen patrolling rooms in the Mausoleum. While they do not attack the player directly, if they see them then they'll scream, throw their lantern near the player and vanish, summoning a collection of difficult enemies which the player must then clear to escape the room. To avoid this, the player must stay out of their line of sight, which is indicated by the light of their lanterns.
Nightwatch behavior varies in two ways. They either remain in place and don't move, but will make 90 degree turns every few seconds, or they attach themselves to a wall and circle around them slowly similar to Guts. In some rooms, Nightwatch is seen guarding treasures such as Golden Chests, an item, or a Teleporter leading the second half of the map. In these cases it is especially vital to not get spotted as triggering a Nightwatch will sometimes deactivate the reward contained in that room.
- If one gets spotted by a Nightwatch, the enemies they have to fight may be especially difficult, as all rooms Nightwatches are found in have a Curse of Darkness effect.
- Nightwatch are affected, even if slightly, by knockback, and can make certain paths inaccessible if pushed far enough.