The basement is accessible through a stairwell in P/S (FNAF2 pizzeria) or the Backstage area (FNAF1). It is the home of Iris (Iris_Blanche), the Trickster Spirits, Foxglove and Buttercup (ZacharyRayYork).
There are several rooms, which include a kitchen, living room area, several bedrooms and a workshop containing spare parts. There is also an "Infinity Closet" that holds a seemingly infinite amount of items belonging to Iris.
- There is a camera for the basement in the FNaF 1 pizzeria, though the button is hidden.
- The pictures and posters on the walls in the hallway of the basement change every Thursday.
- Almost all of the furniture in the basement wasn't actually bought.
- The stairwell's spiral staircase is cleared of spiders once a week, but it still has cobwebs for some reason.