Magical Kanan

When a strange creature collapses near her home, ordinary high school girl Chihaya Hiiragi does the reasonable thing. she takes him in. Turns out he's Natsuki, a being from a magical realm called Evergreen, and he's on Earth to track down five stolen seeds that have the nasty ability to amplify human desires in deeply destructive ways. Once he recovers, he pulls Chihaya into his mission through a transformative kiss, turning her into Magical Warrior Carmine. Now she's stuck dealing with corrupted classmates and a task she never asked for. The setup borrows the skeleton of a magical girl story: ordinary girl, sudden powers, mysterious companion, monsters-of-the-week, but this is a 4-episode OVA from Arms that leans into its hentai roots pretty openly. The school setting and transformation sequences will feel familiar if you've seen something like Magical Girl Lyrical Nanoha or Yuki Yuna Is a Hero, but the tone here goes somewhere those shows don't. Don't go in expecting the emotional weight of Granbelm. this is lighter on plot and heavier on its mature content. It's a short watch adapted from a visual novel, so the story moves quickly without much time to breathe. If you're curious about the overlap between the magical girl genre and adult animation from that early 2000s era, this is a pretty straightforward example of exactly that combination.