Keukegen

A Keukegen is a shaggy mass of pale hair that settles in damp, neglected buildings where sickness already lingers. Its face is almost invisible beneath the coat, and its feet leave dusty tracks across walls and ceilings. It feeds instinctively on foul air and crowded misery, making both worse simply by remaining. Cleaning the place is more effective than chasing it.

Fever Cloud: creatures within 10 ft make a Tough save or become weary for 1 hour. A creature already weary instead takes 1d6 poison damage.

Sun, Air and Water: opening the building to daylight and fresh air removes its DR. Washing the room with clean water prevents Fever Cloud for the rest of the encounter.