Buster Girl is an F.O.E taking the form of a large, muscular female robot. It is black with blue lines over its body, and it has a pair of long, knotted braids tipped with electrical plugs. Its head is a monitor that displays a pair of large, blue eyes. When attacking the party or when the searchlights that it uses to detect foes are turned off, the eyes become a singular, red exclaimation mark and its body turns purple, while the accents on its body become red. It has a backpack on its back that acts as an energy tank. If one pays attention, the words "ENERGY TANK" are written on it.
Buster Girl only appears on the 3rd Avenue of Kamoshidaman. It is stationary, but will attack any enemy that goes under the search lights tied to it. Once the search lights are off, it will patrol in a similar fashion as Chicken Kid, allowing the party to get around it.
It is significantly stronger than Chicken Kid and should not be challenged unless the party is level 23 or above and possesses a skill that can induce the Panic ailment. It is weak to Zio damage, and resists Psi.
It was later revealed that Buster Girl is a Cognition of one of the students taking care of the rabbit in Hikari's primary school, with Buster Girl being those of the girl which it shares the same knotted braids as. The students fed the rabbit with poisonous food given by the teacher and ignore Hikari's warnings. When Hikari spoke against the teacher, they teamed up with the teacher to humiliate Hikari in front of the entire class.