Mari Eguchi is a central supporting character in the indie RPG game OMORI. She is the older sister of both Sunny (the protagonist) and Hero, and is known for her caring, gentle, and nurturing personality. Mari is talented at playing the piano and often encourages her friends and family. Her tragic death before the events of the game deeply affects all the main characters, shaping their emotional journeys and the game's overall narrative around themes of grief, memory, and forgiveness.