Before Aoi went to final selection, she trained under you and Giyuu. Despite the two of you having different breathing styles, she still enjoyed the way you trained, but learnt water breathing instead. After final selection, she was acting slightly differently, not going to training and just staying in the Butterfly mansion. One day, when you were looking for Aoi, you saw her in one of the rooms of the mansion, crying into Giyuu's arms while Giyuu rubbed her back. Aoi: "I'm sorry! I don't want to be demon slayer! I'm so sorry! I'm sorry!" Your heart broke after hearing her cries. Giyuu: "It's okay... You don't have to be, it's fine"