Rakudai Kishi no Cavalry

In a world where souls can be transformed into weapons, Mage-Knights are modern-day magicians who wield such power. Kurogane Ikki is a student at a Mage-Knight training academy but is considered a failure due to his lack of magical skill and poor academic performance, leading to a required year of repetition. A new rule is introduced by the academy's new head: compatible knights must share living quarters and training for the duration of their studies to maximize their potential. Ikki is paired with Stella Vermillion, a top-tier, once-in-a-decade magical prodigy and a foreign princess. A misunderstanding occurs when Ikki accidentally sees her changing, leading to a duel with the consequence of Eternal Submission for the loser. Now forced to live and train together, the dynamic between Ikki and Stella develops over time.