Fumetsu no Anata e Season 3

Hundreds of years after the large-scale battle against the Nokkers in the city of Renril, the world is unrecognizable. Thanks to the immortal Fushi's efforts in dormancy, he has successfully created a world with modern infrastructure where he and every living species can live in peace. When he finally awakens from his slumber, Fushi is elated to try everything this new world has to offer and revive his friends from the past.

While exploring, Fushi runs into Yuuki Aoki, a lively middle school student, who is quick to welcome him and his friends into the house. As the group settles into their new home and learns more about the modern world, Fushi meets Mizuha, Yuuki's friend, who resembles someone familiar to him.

It turns out that Mizuha is the descendant of the Guardians: the people whose only goal is to keep Fushi safe. Like her ancestors, she grows fond of Fushi, which brightens up her life. However, as bizarre events occur when Mizuha approaches Fushi, it becomes clear that this new world is far from perfect.