She is a school sports star. When Head takes a leave from the organization, Marino, under the name Manticore, is promoted to head of Vanishing Age. She is devoted to keeping secret the fact that her sister Mizuno is the West Maiden, thus her reasoning for joining the Glittering Crux. The Yo sisters grew up without parents as their father left them and her mother followed him off the island, leaving Marino and Mizuno alone. Because of the abandonment, Marino has always resented her father. She apparently has feelings for Takuto like her sister. She is the driver of Ayingott, whose abilities allow Marino to see all of the Maidens.
Source from Wikipeida