I once read a manga about a guy who I think was the heir to some Japanese sort of a clan on an island. He was expelled by his father for not being able to get any skills, so he came to the mainland and joined an adventurer guild (where of course he was teased for being weak), joins a party.
He is betrayed by them when faced by a bee-type strong monster. The bee takes him to feed its million worm-like children in a cave. At near death he starts eating them and gets a skill. Then he uses the skill to regenerate and devour all of the worms (the worms are monster hatchlings).
The manga has about 4 to 7 chapters and was probably a light novel too.