Like the other heroes, Ren was initially led to believe Naofumi guilty of the charge of raping Malty, however, he was also, alongside Itsuki, one of the only people to defend Naofumi when Malty cheated to allow Motoyasu to beat him in their dual. He is also the only one of the heroes to actually believe Naofumi when he is later charged with kidnapping Princess Melty and he denies it. Naofumi considers Ren something of a loner, who runs his party like a guild and acts on his own at most times. While it can be said Naofumi does not find him as unbearable as Motoyasu or Itsuki, he still displays petty dislike of him and even tried to kill him when he succumbed to the influence of his Curse Series weapons. He does however see Ren's good side as a hero, and defends him when criticized by Raphtalia's high standards. When Ren refused to take responsibility for his actions in releasing the Spirit Tortoise and getting his comrades killed, Naofumi's opinion of him took a dive, causing him to view Ren as a selfish brat. Finally, after being freed from his Curse Series and finding himself in Naofumi's custody, Ren has begun learning from Naofumi and accepts the faults and responsibilities of his former self and past actions.