Boukensha no Machi o Tsukurou!

Rick is an adventurer who is on a dungeon-exploring journey. While riding a horsecart on the way to town, a fellow passenger (a black slime named Rodriguez) gave him a black pendant. Because of this pendant, the townspeople of Burren thought he was coming to rebuild the town. They requested that he become the head of the village and he declined, but he gave in when the daughter of the previous village head, Kuria, asked him again.

[Taken from Micchi's blog]