異世界帰りの大賢者様はそれでもこっそり暮らしているつもりです

Saito was transported to another world at the age of 15, became a Sage, defeated the Demon King, and safely returned to Japan. He wanted to live a slow life in his hometown, but 19 years had already passed! While saving his former classmate Madonna, who is now a single mom, he was noticed by the mafia and other powerful groups. The more he tries to live peacefully, the more trouble he gets into with these groups. His worries continue...