Kuzuha is a Japanese virtual YouTuber and singer affiliated with the agency Nijisanji who has also worked as a voice actor in anime productions. His character is a vampire over one hundred years old named Alexander Lagusa who does not drink blood and is a NEET gamer. He began his career as an independent VTuber in March 2018 before being scouted by Nijisanji, making him the first VTuber to be recruited by the company, and he officially joined in July 2018 as part of the now-dissolved Nijisanji Gamers branch.

Kuzuha is widely known for his activities as one half of the duo ChroNoiR alongside fellow Nijisanji VTuber Kanae. The unit formed even before Kuzuha officially joined Nijisanji and streams gaming content together and appears as singers at events. The duo opened their official YouTube channel in December 2019 and began a weekly program in 2022. In 2023, ChroNoiR starred in a short original net animation titled ChroNoiR Episode.0 produced by A-1 Pictures, with Kuzuha voicing the character Alexander Laguza, a vampire from the demon world who descends into the human world for a mission. Reviews of the anime noted that his voice acting perfectly encapsulated his role.

As a singer, Kuzuha released his first original digital single Contrail in September 2021, for which he contributed to the lyrics, and it topped the Billboard Japan downloaded song chart. He held his first solo live event on his birthday in November 2021 where he announced his major debut under Universal Music Japan's Virgin Music label and the release of his mini album Sweet Bite. In 2023, he released the single Black Crack, which was used as the opening theme song for the anime Good Night World. As an utaite, his cover of the song King by Kanaria has exceeded 53 million views as of June 2025.

In June 2025, Kuzuha's YouTube channel surpassed two million subscribers, making him the first Nijisanji talent and the first male VTuber in Japan to achieve this milestone. He held his first solo live stream concert to commemorate the occasion, which included celebration messages from notable figures including Ryosuke Yamada, and he announced the release of his second digital single Gimmie More, written and composed by Nqrse.