Juunenme, Kikan wo Akirameta Ten'isha wa Imasara Shujinkou ni Naru

Ten years after being transported to another world. It was more than enough time to awaken from what at first, felt like an exciting fantasy dream world. And on this 10th year 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.