Takuya Arima is a third-year student at Sakaimachi Academy whose mother, Keiko, apparently died when he was young. He often dreams of his mother. Two months prior, his father was killed in a rockfall incident.
He made a promise to Kanna Hatano that he would bring her a psychite to replace her shattered psychite that keeps her alive. While she waits for Takuya, she passes away.
It's later found out that he and Sayless have a daughter together naming her Yu-No.
Upon seeing a photograph Kanna was looking at before her coming death, Takuya arrives and sees that Amanda was alive made the connection that Kanna was his daughter.
He fulfills his promise to her by giving her a psychite that's been crystallized ensuring that it will never break and wishes her to be happy. He bids her goodbye, stating he has someone that's been waiting for him for thousands of years and vanishes before her eyes.
He speaks with his father for the last time and finally sees his mother besides him.
He spends eternity with Yu-No (and Sayless) between the rift of events, from the start of existence from pitch black to universes. Soon, a newly formed sprout springs to life that can remember all events. Yu-No then asks Takuya if he knows the name she has given this sprout (which she calls a child) and he remarks "Yeah."