Maseki Gurume: Mamono no Chikara o Tabeta Ore wa Saikyou!

A reincarnated boy with a secret skill aims to become the great king! Ein reincarnated as a noble with the skill "Toxin Decomposition EX". The skill was not something he wanted, so he was disappointed...but then learns that he has a very rare talent to absorb magic power by eating magic stones. They even taste good! He then found out that his real identity was a prince of the largest kingdom of the continent. He was luckier than he thought! Now, with his loving, beautiful mother and clever fiancee at his side, Ein's quest to become the greatest King begins! Source: BookWalker Global