Willow

 is a ghoul, the self-proclaimed sentry of the Underworld in the year 2277.

Interactions with the player character
She persistently addresses the Lone Wanderer as a "tourist".

Daily schedule
She can usually be found on the Mall, wandering around just outside the entrance to the Museum of History. She seems unconcerned with standing around a heavy combat zone, claiming that the Super Mutants don't attack her, as they seem to ignore Ghouls in general.

Appearances
Willow only appears in Fallout 3.