Mayuzumi Kai

Mayuzumi Kai (黛灰) is a male Japanese Virtual YouTuber and a member of Nijisanji. He debuted alongside Ars Almal and Aiba Uiha, known as the trio "Blues" (ぶるーず).

Profile
An aloof and talented white-hat hacker who began livestreaming as part of an undercover investigation. He rarely goes outside and orders everything online.

Personality
Cool-headed and reserved, Mayuzumi is known for his monotone way of speaking and his blunt and sarcastic humour. He will often speak casually to his seniors instead of using polite speech, much to their annoyance. Mayuzumi will often suddenly act out of character through exaggerated voice acting or peculiar video editing; most famously, at the suggestion of his viewers he completely reversed his personality and acted in an energetic and polite manner.

As shown through his frequent collab and call-in livestreams, he gets on well with many livers including those outside of Nijisanji such as Natsuiro Matsuri from hololive. , and his own illustrator Ichijiku.

Due to his quiet personality, others often become excited if they are able to make him laugh.

Aside from the usual VTuber game titles, he most often plays indie games.

Background
Mayuzumi made his YouTube debut on 29 July 2019.

2019
In October he revealed he had cataracts in both of his eyes and would have to limit his streaming frequency as they were treated.

2020
In February he resumed regular streaming after recovering from surgery to remove the cataracts.

On 3 July, Mayuzumi announced he would be in his official 3D model debut on 10 July. He unveiled his official 3D model on 10 July as scheduled.

Fans

 * The name for his fans is "ListeNerds".
 * He begins livestreams with his famous "Do-mo" (どーも lit. Hello) catchphrase.

Trivia

 * Notable units within Nijisanji:
 * "メッシャーズ" (Mescher's ) - Mayuzumi, Saegusa Akina, and Fuwa Minato (These three all have highlights in their hair.)
 * Notable units outside of Nijisanji:
 * "Natsumatsurikkai" (ナツまつりっかい), along with Natsuiro Matsuri, Kuroki Natsume and Rikka.
 * Color: #086776
 * Mayuzumi has a mascot called Iroki Shirou who is based on the color of his inner hair. He's a turquoise strand of hair wearing a happi, traditional Japanese festival wear, and a headband. He speaks in an old Edo speak/dialect, and has very loud and energetic but masculine and old-fashioned mannerisms.
 * His favourite anime is Serial Experiments Lain
 * He is weak to horror games.
 * He uses "X" in his Twitter username as the Greek letter "χ" can be pronounced "Kai".
 * As "χ" can also be pronounced "Chi", he uses it in his channel header for the phrase "Mayuzumi χannel"
 * He wrote the lyrics to Aiba Uiha's first original song, "Yume e Mukatte Maenarae!".

Media

 * 黛灰/Kai Mayuzumi【にじさんじ】 - YouTube channel
 * Mayuzumi's corporate profile on the official Nijisanji website
 * @mayuzumi_X - Twitter account
 * @BBash_Shell - Sub Twitter account

Further readings

 * 黛灰 (まゆずみかい) - Unofficial Nijisanji wiki