Wererat

A Wererat moves between human shape, giant rat, and a lean hybrid suited to cellars and narrow passages. It survives through networks, hidden food, and information traded among people whom respectable society ignores. Some infest settlements as predators; others build secret communities and become ruthless only when discovery threatens the whole nest.

Sewer Bite: piercing, melee 5 ft, +6 to hit, 2d8+4. A wounded target makes a Tough save after the encounter or develops a fever and becomes weary the next morning.

Every Exit Known: the Wererat gains +2 AC while within 10 ft of a passage too small for a Large creature. Blocking two exits removes this bonus and may force negotiation.