Kodama no Tani

Neil Ryder is in no hurry to graduate from university. Though brilliant (he did earn that scholarship!), he uses his talents to make money instead. Meanwhile, the king is dying and the crown prince is missing… Also includes “Fuku’s Many Travels,” diary-like entries of Fuku and his father’s adventures around the world. (https://mangadex.org/chapter/70f23c3f-62b2-4178-b53d-dd868f991f9d) of Gunjou Gakusha contain a short sequel story sharing some characters.