Double is a shapeshifting creature working under the Trinity, responsible for ensuring that the Skull Heart falls into the "right" hands and manipulating events according to the goddesses' will. Her current guise is as a nun under the name Agatha Gloomfoil. Her home stage is the Grand Cathedral, but Gehenna is also referred to her "domain" and is even implied to be an extension of herself. Despite her taking on a female form as a disguise and her combat stance being feminine, her gender is still listed as Unknown. Which may be because she's not actually human and as such has no true gender. The nun form that she takes is based on no one in particular; it's just a form she takes to blend in at the cathedral. Double chooses a nun form in order to manipulate people with religion. Double's true form has been long forgotten. But the face in the nun form does have hints of what her original image was. Double is speculated to have been created by the Trinity as she shares a few physical traits from each member. Venus views Double as a maid or a butler, although it’s not quite as straightforward as Double represents many things. Double is an enigmatic character who lacks a distinct motive or will that most of the cast have and rarely emotes. She mostly maintains a stoic demeanor when conversing with someone. However, she has shown bouts of pure rage and hatred when it comes to characters like Squigly (Squigly refuses to obey Marie's orders) and Eliza (Eliza killed Aeon and Venus). Double's encounter with Eliza implies that she has an unspecified connection to Queen Lamia, such as being her avatar or 'shadow'. She has been shown to be a manipulative figure who will do anything to further her agenda and create Skullgirls. Even if she follows their orders, Double will not hesitate to eliminate a Skullgirl should they put The Trinity's plans to a standstill