MAGIC STONE GOURMET: EATING MAGICAL POWER MADE ME THE STRONGEST

Goddess has made Ein reincarnate as a nobleman--a big chance. However, the skill he got from her "Toxin Decomposition EX" is a lame one. One day Ein learns that he has a very rare talent which makes him able to absorb magic power by eating magic stones. Also he is told that he has other identity as a prince of the largest kingdom. With his loving, beautiful mother and clever fiancee at his side, Ein's quest to become the King begins--! (Source: Kadokawa) — Description from AniList community (anilist.co).