Koushakuka No Ryouriban-sama: 300-nen Ikiru Chiisana Ryourijin

A boy named Lushel, whose father is the "Sword Saint", gets disowned in the mountains because of his weak constitution. He is forced to live a life of survival, alone, in the mountains where magical beasts live. However, he found out by chance that monsters can be consumed, and he was able to acquire skills by eating them...!...