Yakutatazu Skill ni Jinsei wo Tsugikomi 25-nen, Imasara Saikyou no Boukentan / Двадцать пять лет развивая бесполезный навык, я стал сильнейшим искателем приключений

A skill useless from the beginning, "Restoration." Regardless, in order to save a childhood friend who sacrificed her body to protect him, Tooru spent twenty-five years developing the skill. Once completed, the skill could completely defy the world’s common sense. Tooru, the girl, the naughty child they picked up in a back alley, and the old landlord lady join together as companions, setting out on an adventure to become heroes. A man who lived through the depths of despair decided to move forward and widen his horizons.

(Source: Shousetsuka ni Narou, translated)