Mari is an Arume spy under Alice. Mari was trained by the military at a very young age to be an elite foot soldier, made specifically to kill, to win by attrition. She was made to be a machine, and performed very well at her job. Alice noticed these skills of hers and decided to employ her as a personal assassin. Mari is able to pick things up very quickly thanks to a lifetime of training, languages, fighting techniques, etc. Alice decided to employ her as a spy since she did very well as an assassin, and was constantly picking up new skills. She was to spy on the Empress's sister, Izanami in San Angelo. When Alice died she took it upon herself to kill the Royal sisters since Alice ordered Mari to kill them if anything went wrong. She however was stopped by Jim Black, and thrown imprisoned by the resistance.
Mari has a slim but muscular body since she needs to be nimble and agile, but also strong. She has strong thick thighs and an above average chest size. Her hair is long and dark brown and she has brown eyes. She used to sport a maid uniform at San Angelo but now wears a gray prison uniform.
Mari is very cold hearted to most people, and lacks empathy. That doesn't mean that she can't get emotional though, her job is the most important thing to her since that's her very reason for living. She's a bit naive, and doesn't know what to do in social situations. She is very intelligent, but lacks emotional intelligence which she beats herself up over.