Age: 15 (when humanity disappeared), 17 (present) Masashi keeps an optimistic view of things, believing that humanity isn't extinct and that the people who disappeared will return. He tends to a vegetable garden and raises chickens, and is always looking to gather more knowledge on survival and the Phantoms. He used to live in Suginami City with his parents and little sister, Kiyomi — whom he still sees visions of occasionally. Masashi claims to not have liked school too much but was very good at Math, to the point of solving a well-known mathematical problem at only 15. The mysterious white-haired man with an eyepatch that leads Sanae and Anna's group, and Yaeko's group, at the same time, is revealed to be a future Masashi from a different timeline. Along with that timeline's Anna, Yaeko and Sanae, he discovered time travel in order to save humanity from a meteor shower that would've led to its extinction.