The Young Merchant (青年商人 Seinen Shōnin) is a cunning business entrepreneur whose goal is to simply expand his fortune. He uses the Demon King's exploits as a means to. Eventually, he learns from the Hero about his and the Queen's plan and agrees to help them while taking the opportunity to further line his pockets.
Demon King/Crimson Scholar: Attracted to her beauty and won over by her intelligence and shrewd mind, the young Merchant had shown a strong interest in her to the point of asking for her hand in marriage after their first meeting. He continues to think about her and will use an excuse to go visit her. His shrewd character allowed him to notice that the person he was meeting with in episode 7 was not the Crimson Scholar, but the older sister maid when she was told by the Crimson Scholar herself to wear a fairy ring to pretend to be the Crimson Scholar when she was away.