Overview
SEKAI is the second voice synthesis software in KAMITSUBAKI STUDIO’s Musical Isotope series, built from the vocal data of virtual singer ISEKAIJOUCHO. It inherits the transparency and narrative quality characteristic of the original voice.
Joining the series after KAFU, SEKAI further enriches the Musical Isotope product line. Its voice quality tends toward clarity and softness, occupying a differentiated position from KAFU’s more youthful character.
Role and Creative Position
SEKAI’s voice source derives from ISEKAIJOUCHO — the V.W.P member known for “world-system” narrative and emotional expression. As a result, SEKAI is frequently used in the UGC ecosystem for songs that require transparency, lyricism, and narrative depth.
Like KAFU, SEKAI is not merely a tool but is positioned as a “voice character” within the creator community — with its own visual identity and settings, connected to yet independent from the original singer ISEKAIJOUCHO.
Activity History
2021
- October 23: The production of Musical Isotope SEKAI was announced during the end credits of ISEKAIJOUCHO’s 1st ONE-MAN LIVE “Anima”.
2022
- February 28: Pre-orders for Musical Isotope SEKAI began.
- April 29: Musical Isotope SEKAI (CeVIO AI voicebank) was officially released.
2023
- April 29: SEKAI’s 1st compilation album Metaphor was officially released.
- December 10: “Musical Isotope SEKAI TALK EXTENSION collaboration with VOICEPEAK” (speech synthesis software) was officially released.
2024
- June 9: Performed at “V.I.P 1st MINI LIVE ETHEREAL WORLD”.
Representative Works and Related Entries
SEKAI does not release traditional music works but exists as a creative tool. Songs created with SEKAI are continuously produced by the UGC creator community.
Useful related entries:
Basic Profile and Character Setting
SEKAI is a CeVIO AI singing-synthesis product and character based on ISEKAIJOUCHO’s vocal data. It inherits transparency, lyricism, and narrative colour from the source voice, but is not ISEKAIJOUCHO herself.
| Item | Detail |
|---|---|
| Voice source | ISEKAIJOUCHO |
| Platform | CeVIO AI and VOICEPEAK TALK EXTENSION |
| Character design | reoen |
| Key projects | DIMENSION, Metaphor, V.I.P |
Representative Songs and Creator Ecosystem
SEKAI’s music is primarily produced by UGC creators rather than released as a traditional personal discography. The official “DIMENSION” demonstration cover and the first concept compilation Metaphor are useful entry points. Songs made with SEKAI should not be placed directly in ISEKAIJOUCHO’s personal catalogue: the voice, visuals, and projects are related, but the records remain separate.
Name and Identity Boundaries
SEKAI is the voicebank and character; ISEKAIJOUCHO is the virtual singer who provides the source voice. V.I.P and other joint projects place multiple musical isotopes together without erasing the distinction between products and source artists.
Related Projects / Setting
SEKAI is part of the Musical Isotope Project, initiated by KAMITSUBAKI STUDIO to develop voice synthesis software based on its virtual singers’ vocal data using AI technology. KAFU (based on KAF) and SEKAI (based on ISEKAIJOUCHO) are the current core products.
Contact: musical-isotope@kamitsubaki.jp
References
- Musical Isotope official website: https://musical-isotope.kamitsubaki.jp/
- KAMITSUBAKI STUDIO Musical Isotope page: https://kamitsubaki.jp/artist/musical-isotope/