That’s when the “fall” begins.
Toshoshitsu no Kanojo: Seiso na Kimi ga Ochiru made (図書室ノ彼女～清楚ナ君ガ堕チルマデ～), which translates roughly to "The Library Girlfriend: Until the Pure You Falls," is an adult-oriented original video animation (OVA) series that first debuted in late 2020 and continued into 2021. Produced by the animation studio and published under the Pink Pineapple toshoshitsu no kanojo seiso na kimi ga ochiru m 2021
The “Seiso na Kimi” concept also spawned a subgenre of “pure male protagonists” in 2022-2023 indie VNs (visual novels), such as Library Labyrinth and Her Quiet Voice — both directly inspired by this work. That’s when the “fall” begins