Kasane Teto (重音テト) is a Japanese UTAU who was originally created as a troll "VOCALOID" by fans. Her surname 重音 (Kasane) literally means "heavy sound" or "overlapped sound", so these interpretations are widely accepted among fans. TWINDRILL, however, has not released any announcements about the meaning of the name.[3] Her name テト (Teto) comes from Tetopettenson, a parody song of Le Beau Tambour. Although her voicebank is only for use in UTAU, many people still mistake her for a VOCALOID.


Following the rising popularity of Hatsune Miku, "Vippers" (Vip News Bulletin@2ch users) schemed a troll "new VOCALOID release" as an April Fool's joke. Sen (線) provided the rough sketch and Nobuyo Oyama, a spoof for Doraemon's former voice actress Nobuyo Oyama, provided the vocal. The Teto project continued after the troll campaign, and her vocal was recorded again for the use on UTAU, which vocal synthesis software was released two months earlier. UTAU and Teto were both unnoticed among VOCALOID composers at first, but during the last half of the year of her release several creators started composing songs for Teto, causing her fame to be established during following year. The voice provider's name reading was then changed to Mayo Oyamano (小山乃 舞世 Oyamano Mayo) to avoid unnecessary confusion.

Teto was given official acceptance to piapro on April 1, 2010, and to Project DIVA on October 10, 2011.

Impact on VOCALOID

The first cover song using Teto was created as early as on April 6 of the year, and her signature song "Mimi no Aru Robot no Uta" was published on June 10 by Mimirobo-P. Since then several creators including Lamaze-P, Telmin and Death Ohagi started to create Teto songs. Some of these early works are "Fake Diva", "Triple Baka", "Kasane Territory", and "Popipo Mk-II".

This trend changed on August 1, 2009, when UTAU was updated and VCV voicebanks became available. Teto's VCV voicebank was released on October 20, 2009 and her singing became more natural than before. This evolution made more DAW users turn their eyes towards Teto. Many Teto songs were posted to Niconico, and Teto and UTAU established the place among VOCALOID.


Since the adoption for Project DIVA in 2011, Teto had several unusual chances for a non-VOCALOID character to appear in media.

Media Appearance

Japanese record label Avex released a CD album containing Teto songs on October 10, 2012.

From April of 2013 to March of 2014 Teto was adopted as an official character for Hokkaido Broadcasting Co., Ltd.

The Kabuki play Kuruwa Kotoba Awase Kagami, where Teto acted as a side character, was performed on April 29, 2017. The story was inspired from Yoshiwara Lament, one of the most famous songs of Teto.

In the CD album 手塚治虫と冨田勲の音楽を生演奏で, released on September 6, 2017, Teto collaborated with Miku.


An official nendoroid has been made for Teto.


In Maker Hikōshiki Hatsune Mix, Teto makes a cameo appearance in chapter 14, Kagamine Mix.

Video Games

Teto, along with other non-VOCALOID characters, is a playable character in the Project DIVA series.

Voicebank Libraries

Product Information
  Genre: Pop, Anison  Tempo: 70~150 BPM  Range: A#3~E#5
Package details
Teto is held under license by Team TWINDRILL and usage of her image and voicebank must comply with their licensing agreement. Her initial release is BOUCALOID on April 1, 2008 with triphones on September 17, 2011, and her second release is BOUCALOID APPEND on October 1, 2012.
Vocal traits as noted:

As noted:

  • Kasane Teto has the next banks available for download:
    • Diphone (Original Consonant-Vowel bank from 2008)
    • Triphone (Regular Vowel-Consontant-Vowel bank)
    • Appended (with ending breaths and rolling "r" as found in German and French)
    • Sasayaki (Extra Whisper VCV bank)
    • Rikimi (Extra Growl CV bank)
    • Sakebi (Extra Shout/Power VCV bank)
    • English (CVVC bank, it's recommended to use an external plugin to input lyrics).
Software issues as noted:
  • Needs a special surfix to get the Extra voicebanks working (囁 for Whisper, 力 for Growl and ↑ for Shout/Power.
  • Western users may need to convert voicebanks to romaji if the computer's region settings are not configured correctly.
  • Users have reported that her English bank has small flaws (such as mistaking si for shi) but gives a decent, Japanese-accented English.

Additional information


Kasane Teto's character status

She can be downloaded for free from her website. She is also regarded as one of the most used UTAU in Japan, if not the most used.


Since her first voicebank release, Kasane Teto have received a very positive response from the public. Kasane Teto has more than 20.000 videos starring her at NicoNico.

  • She is regarded as one of the primary reasons UTAU became popular due to her infamy as a fake and fame as a character. Her fame lead to the raise of the UTAU "Vipperoids".
  • She is recognized as the first UTAU with a recorded voicebank, as Utane Uta's is borrowed from AquesTalk Female-1, which is machine synthesized.
  • She, Momone Momo and Utane Uta were referred to as the "3 UTAU Girls", due to their fame.

She has made guest appearances in official VOCALOID media by Crypton Future Media such as Project Diva. In fact, because of her fame and constant guest appearances alongside VOCALOIDs, she has been often been mistaken as a VOCALOID.

  • She is the first VIPPERloid.
  • She is the first UTAU character to appear in the Project DIVA videogames.
  • She is the first "non-VOCALOID" character that is licensed by Crypton Future Media to be in a Project DIVA game.


  1. Q&A 性別がキメラってどういうこと?
    What does it mean "gender: chimera"?
  2. Q&A テトは本当に31歳なの?人間に直すと年齢は半分になるの?
    Is Teto really 31 years old? Her human age should be counted the half?
  3. 重音テト制作時に参加者の一人から提案されて採用された苗字ですが、その由来は不明です。
    (This was) a surname suggested by a contributor and we adopted it, but the source is not known.

External links

Japanese Kasane Teto Official website Link
Japanese Kasane Teto Blog Official blog Link
Japanese atWiki Kasane Teto Wiki Link
Japanese @twindrill_teto The official Twitter account for Kasane Teto Link
Japanese TwinDrillTeto Official YouTube channel Link
English UTAU Wiki Kasane Teto page Link
English UTAU Wiki 2.0 Kasane Teto page Link


Start a Discussion Discussions about Kasane Teto

  • Teto Did become a vocaloid!

    36 messages
    • Yes, because she apears in a game where only real vocaloids attend she’s suddenly a vocaloid (sarcasm if you can’t tell).
    • IzunaSugar wrote:Yes, because she apears in a game where only real vocaloids attend she’s suddenly a vocaloid (sarcasm if you can’t tel...
  • "But Teto DESERVES to be a vocaloid >:(!!!!!!!!!1"

    187 messages
    • I said “honestly, I prefer Meji” because I love Meji better than Teto, not because I want her to be a vocaloid. Smh
    • If nobody minds, allow me to copypaste something I said some months ago in the comments section of the Kasane Teto article: If Teto wa...