Maseki Gurume: Mamono No Chikara O Tabeta Ore Wa Saikyou!

Story:

Mamono No Chikara O Tabeta Ore Wa Saikyou! "I can only gain strength in this world by eating magic stones!" I once received an offer from the reincarnation of the Goddess. She gave me a skill as a reward, but it turned out to be just a cleanser. Ugh, it's useless! I even got ridiculed by my own family for being so lucky. But I soon realized that this skill helped me eat magic rocks and get stronger! Later it became known to me that I am the prince of a neighboring country! In the palace, I take on experiments with magic stones and various training. That's how I can become the strongest of men! This manga tells the story of a young man who wants to be the strongest king, and a persistent bride with a pair of girl knights!