100-nin no Eiyuu wo Sodateta Saikyou Yogensha wa, Boukensha ni Nattemo Sekaijuu no Deshi kara Shitawaretemasu @comic

Raising a hundred heroes and ending the war with an evil god, Eisen saved the world. Having received a great injury from protecting the heroes, he left for the Other World to recover. In that time, the heroes made use of their abilities to contribute greatly to the development of the world. Longing to meet again with the master they admired, they reported to him of their achievements in detail. Reading their letters, Eisen makes a decision to set out and pay each of them a visit as he travels the country to sightsee.

(Source: Shogakukan, translated)