Let's Buy the Land and Cultivate It in a Different World (Manga) Vol. 8

After being summoned to another world, Kidan possesses the power of the Supreme Wielder. Together with the mermaid Plattie and the dragon Veel, he has built a homestead on the frontier, and his farm's only getting larger. Elves, demons, witches, and humans are all welcome. Then one day, Plattie’s older brother, Prince Arowana, pays a visit to the farm to say goodbye. He's departing on a journey for self-improvement! What will his sweetheart Puffer do...?!