Lampwicker

An example of Undead raised to fulfill a specific niche role within The Citadel, a Lampwicker's purpose in un-life is to ensure the place is well lit at all times. After all, even the Dark Arts benefit from adequate lighting.
Erroneously considered to be intelligent undead, especially when compared to a Candleskull, A Lampwicker's mind is in reality extremely simple. Their decision making consists entirely of a hierarchy of tasks to be completed and little else.
A Lampwicker's tasks are as follows:

1. Restock lighting materials if used up.
2. Move to an unlit light lamp/candle/torch source.
3. Light the unlit light source.

This repeats forever.
Nobody is quite sure exactly how a Lampwicker senses that a light has gone out, only that this is so and requires replacing and re-lighting. They are utterly headless to any threats or obstacles in their way, and will happily attempt to path straight through locked doors, dangerous traps, and even well armed and angry intruders that may be responsible for extinguishing the light in the first place. Should a Lampwicker be slain in the course of their duties, their internal list of tasks somehow instantaneously gets reassigned to other nearby Lampwickers. Should a Lampwicker become stuck in performing their duties, such as when they attempt to walk through locked doors, they require the assistance of a Warlock. It is a closely guarded secret as to how a Warlock resets a Lampwicker's mind, but it often involves smacking the undead over the head with a heavy tome.