Level 4 Human in a Ruined World - Chapter 9

The Hero’s party was attacked by a large group of powerful devils. The party will no doubt be annihilated if this were to go on.

After breaking up with his girlfriend, he accidentally acquired a genius system and rose from there against the heavens, becoming invincible..

- Description from Novelupdates

Have you ever seen exposing holy vein?

Quinn Winter is a young man from another world. One day, he is suddenly chosen to become the new Demon King. But the Demon Kingdom is in big trouble – it's losing a terrible war against the human kingdom called Gran'le.To help his people, Quinn comes up with a risky plan. He will sneak into Gran'le and learn their secrets. But things don’t go as planned. A powerful noble sponsors him, and he ends up joining Heavenward Academy, the top school for training future heroes.At the Academy, there's a big challenge called the Selection. The best students become Paladins – magic knights who fight demons. Quinn doesn’t want to become a Paladin. He is a demon king! But now, he’s stuck in the Selection… and if he wins, he’ll become the very thing he’s supposed to destroy.He started the day badly. Now, things are getting even worse.