Caligula or (The Caligula Effect in English) is a role-playing video game series developed by FuRyu and Aquaria(Original)/Historia(Overdose/2) and ported for English speaking audiences by ATLUS USA and NIS America.
The series consists of the following games:
- Caligula (Game) (turned into a 2018 anime of the same name, and remade as an updated game "Caligula: Overdose")
- Caligula 2