Juunenme, Kikan wo Akirameta Tenisha wa Imasara Shujinkou ni naru

Story:

On the 10th year after his transfer. It was more than enough time to awaken from what at first, felt like an exciting fantasy dream world. And on this 10th year, the protagonist, Tooru (Wasa Tooru), gives up searching for a way to return to Japan, after being unsuccessful for so long. It was then that a job offer found its way to him - it was to be the bodyguard of twins who have knowledge of Earth.