Arthur Penn reappears and is revealed to be the Batman supervillain The Ventriloquist. Originally, his role as Ventriloquist was going to be cut from the season due to it being shortened. However, FOX was granted season 5 two extra episodes which allowed the producers and writers of the show to go ahead and use Penn as the Ventriloquist.
The supervillain Jane Doe debuts. In the comics, Jane Doe is an Arkham Asylum inmate who stalks people, learns everything about them, murders them, and steals their identity, disguising herself and living as them.