My Girlfriend is Saiki Kusunoko

Naoto Yamashita, a failed art student, travels back in time to become a noble Celestial Empire traveler and a high school student in Japan. Here, he discovers his childhood sweetheart, Kusunoko Saiki. His best friend, Sakuta Azusagawa, is also a student at a strange club called the Service Club. Meanwhile, a rising manga artist, Yumeha Ashiroki, is also in the manga world. However, none of this has anything to do with Naoto Yamashita. As he desperately prepares to pay off his thirty-year mortgage—in short, this is the story of an ordinary high school student's ascent to become Japan's top manga artist.