Kanade's cousin and a college student. Ritsu made a suppository for Tomoharu when he had a fever. She helps Uzumasa repair the Asura Machina and she also helps Uzumasa repair Shuri's arms and legs. Ending credit shows that Ritsu developing a new suppository.

Spoiler

(First World) Naotaka's girlfriend and the chief of "La Croix" which is the head office of the High-energy Physics Research Organization. Ritsu is the woman who Tomoharu from Second World often see in his dream and echoes of memory. She askes Tomoharu and Kanade from First World "Is that your decision?" when Tomoharu choose to become a Hagane's handler in order to save Misao and stop the destruction of the First World and She asks the same question again when Tomoharu from Second World asks "Is there a way to stop it"? just like how Tomoharu from First World asked to Ritsu from the First World. Ritsu thanks Tomoharu for one last time for saving the First World to make future between her and Naotaka possible before Tomoharu depart to Second World.