TV-Series
Description
Mari Sasshō is a secondary character in the Rail Wars! series. She is a second-year student in the Passenger Transport Department and a classmate of Naoto Takayama. She participates in the on-the-job training program of the Japanese National Railways and also works part-time as a maid at a cafe frequently visited by members of the Fourth Peacekeeper Squad. Mari has short orange hair and light brown eyes, and she is almost always seen with headphones around her neck. Her personality is cheerful, outgoing, and lively, which helps her make friends easily and brings energy to those around her.

Her primary motivation is to become a dining car attendant, a goal she pursues by undergoing training with Japan Shokudo, a company that provides in-car dining services. She has already received an unofficial job offer from them. Mari is also a dedicated railway recording enthusiast, often carrying a pink digital voice recorder to capture the sounds of trains as she travels across the country. This hobby ties directly into her most notable ability: an exceptional sense of hearing. She can identify different trains solely by their sound and can describe with precise detail anything she hears. This skill occasionally proves useful in the events of the story.

In the original light novel, Mari becomes involved in an incident while working as a dining car attendant aboard the Hokutosei No. 3. During that event, Shō Iwaizumi puts himself in danger to protect her, which leads Mari to develop romantic feelings for him. In the anime adaptation, her role is expanded; she appears more frequently due to a change in her training assignments, and her relationship with Naoto Takayama is given greater emphasis. In the anime, she is portrayed as having an unexpectedly detailed knowledge of Naoto, which arouses jealousy among the other female characters. She herself becomes the third heroine to show signs of jealousy over Naoto, adding to the series' romantic dynamics.

Mari maintains a friendly and supportive presence throughout the series. She interacts regularly with the Fourth Peacekeeper Squad and provides a familiar, reassuring connection outside of their official duties. Her development is subtle but consistent: she grows more confident in her career path and becomes more comfortable expressing her feelings, whether toward Naoto or Shō, depending on the adaptation. Overall, Mari Sasshō is a warm, enthusiastic character whose passion for railways and sharp hearing make her a memorable supporting figure in the Rail Wars! story.