Introvert Tsubame Wants To ChangeIntrovert Tsubame Wants to Change; Inkya na Tsubame wa Kawaritai; 陰キャなつばめは変わりたい; La Chica Introvertida Quiere Cambiar; 徐々に陰度が下がっていく陰キャちゃん; Yinka-chan, Whose Yin Level is Gradually Decreasing

The story is about a university student, Tsubame Takashina, who has no presence, meets a boy, Taisei Kyogoku, and tries to overcome her negative attitude little by little.(https://www.pixiv.net/en/artworks/109457638) (Not included in the Pixiv Series Index)(https://www.melonbooks.co.jp/detail/detail.php?product_id=2005392)