Marin is Rushia's partner in crime. She loves to take care of people that have been abandoned. For example, she has taken in Hiroshi (a stray child), a stray kitty, and Soo In (a girl who was sold off by her father).
Marin has problems about her past in which she was abandoned herself, and that makes her want to protect everyone else who is abandoned. She works under the Iwashi family and is partners with Rushia, which codes names Francesca and Bullet, respectively.
Her weapon of choice are two sharp and weirdly-shaped axes. Her body is made out of carbon steel which is why she has many stitches along her arms and her legs. In addition to her body modifications, her teeth are also made out of boron nitrate, making her bites very deadly.