Kizuna AI

Kizuna AI debuted in November 2016 as the creation of Tokyo company Activ8, and is widely credited with coining the term “Virtual YouTuber.” Voiced by actress Nozomi Kasuga and animated through motion capture, the character was never literally powered by machine learning — the “AI” in her name doubles as a pun on the Japanese word for love — but her entire persona was built around being a self-aware artificial intelligence trying to connect with humanity through technology. At her peak she was the most-subscribed VTuber on YouTube, spawning the entire industry that followed.

When the fictional AI built a real one

The project’s relationship with AI stopped being purely thematic in 2022. Ahead of Kizuna AI’s February 2022 “indefinite hiatus,” Kizuna AI Inc. announced #kzn — a singing voice library for CeVIO AI (and later VoiSona) built from her voice using deep-learning voice synthesis. A prototype appeared on stage at her final concert to sing a duet with her, and #kzn shipped to the public in February 2023 as a tool anyone could use to keep making music in her voice while she was “asleep,” explicitly framed as a hub to keep fans and creators connected.

Kizuna AI resumed activity in February 2025 as a music-focused artist under the styling “KizunaAI,” releasing the single “Kamone” and planning an album. Between a persona premised on friendly artificial intelligence and a company that voluntarily turned that persona into a working generative-voice product, the Kizuna AI project sits firmly on the embrace side of the AI debate — using the technology as a creative extension rather than treating it as a threat.