A leader is an upgraded version of a normal enemy type. Leaders appear randomly in rooms, replacing a normal enemy of their type. Only one leader can appear in a room.
- Leaders have a definitive red color
- Leaders have much more health than a normal enemy of their type.
- When damaged, leaders display a boss-style health bar at the top of the screen. This also shows the leader's name. There are several possible leader names for each enemy type.
- A leader's attack is normally an upgraded version of the basic enemy's attack with some improvement beyond increased damage. Sometimes the leader gains an entirely new ability.
- When killed, leaders drop an item.