Isekai de Tochi wo Katte Noujou wo Tsukurou

As our humble office worker Norio Itonami is suddenly summoned to another world, it looks as if he'll be sent to a battlefield—however, he has no skills to speak of, and is deemed to be useless. He negotiates with the king and receives a plot of land—an empty, deserted plot of land, with no inhabitants in sight. Norio holds something he couldn't bring himself to tell anyone: The Master of Supremacy, a gift which will grant him the most comfortable of lives in this world. Hereby begins the Norio's colorful story—having a mermaid he fishes declare herself his wife, becoming neighbors with the Undead King, this is his busy but enjoyable life—and now a dragon appears?!

(Source: Gentosha Comics, translated)