Nezuko Kamado is the younger sister of Tanjiro in Demon Slayer: Kimetsu no Yaiba, the manga series that began in 2016 and became a hit anime in 2019. Turned into a demon, she rarely speaks clearly and mostly communicates through soft hums, which makes a clear cute call especially memorable for fans. Short voice clips like this spread on soundboards and phone sites as ringtones alongside other anime girl calls such as Onii-chan, onii-chan and Tuturu. The chan honorific signals affection, helping explain its lasting use.