Name: Kou 1 Desu ga Isekai de Joushu Hajimemashita
Latest Volume is Vol.25
Site: https://www.foxteller.com/novel/573/im-a-high-school-student-but-im-a-castle-lord-in-a-different-world
There is a previous page for this novel, which is currently dead (inactive for 120 days, and all links have expired.) (×_×)

To whoever is willing to pick it up, my heartfelt appreciation to you in advance. (づ ᴗ _ᴗ)づ♡