No Dates, Mr. Charming

Ten Halls, a first-year student of a university. He was originally a weak and frail person with poor stamina. He was nicknamed the bookworm.
He had a fortuitous encounter in a museum and obtained a mysterious ancient power. Every time he encountered danger, his personality would change greatly. He would use the ancient power to summon demons to fight. Later, he learned that he was the reincarnation of the ancient king. He led the Demon Gods to fight against the Heavenly Kings…