Kekkaishi - Season 1 Episode 49 Sad Demon Flower

Aihi rescues Tokine who was about to fall into the depths of the castle. Aihi takes Tokine into her lab and Aihi's past was revealed. Appearently, Aihi lacks the evil aura that most Ayakashi has because she fell in love with a human. Shortly after Tokine leaves, Kaguro appears in front of Aihi and the two of them engage in battle. Kaguro easily defeats Aihi despite Aihi being a high class Ayakashi. Kaguro says the reason for her defeat was because she became weak from losing her desire to eat humans, but Aihi claims that Kaguro is also weak because he is insecure. In the exact moment where Kaguro is about to destroy Aihi, he senses Yoshimori's presence and heads off to him. Aihi transforms into her plant form and releases her dandelions; one of which makes its way back to the human she loved who is now an old man.