Aasu Masamune, widely called Earth Masamune, attends Yukishina Junior High School as a second-year student. Originating from the year 2011, he became the fifth person to arrive at the castle through the mirror's portal. An avid video game enthusiast, this passion forms a core part of his identity. His dedication to gaming directly inspired Subaru Nagahisa to pursue a career as a video game designer.