Based on the title provided, you are likely referring to the adult isekai series (also known as My Classmate is a Princess Knight or My Slave IS Classmate in some translations). This series revolves around Tōru Odamori , a "Slavemancer" who builds a harem by magically dominating women in a fantasy world, including his former class president, Kirika . Core Romantic and Relationship Dynamics
: A key turning point occurs when Toru’s magic reaches Level 6, allowing him to restore his slaves' original personalities. However, the magic remains absolute: they must still serve and respect him as their master, creating a paradoxical dynamic where they have their old selves back but are magically compelled to be obedient. Download My Sex Slave IS A Classmate PC Game 2003
If you were looking for a different "Classmate" story with actual romantic development, you may be thinking of: Enslavement Magic - My Classmate is a Princess Knight Wiki Based on the title provided, you are likely