Mari was one of the members of The Original Smoosh 2000 years before the formation of the current one. Despite the passing of two milennia, Mari has evidently not aged at all, living in a realm outside of The Universe along with Queeny. Mari usual clothing apparently consists of a dark green robe, and she appears to have a rather laid-back personality. She is also a bit of a stoner, and seems to still be on good terms with Nintendoki.
Recently, Nintendoki has apparently decided to temporarily release Mari along with Queeny from their realm in order to spy on Smoosh while visiting a world known as Haruvia.