Virtual Character Encyclopedia

SEKAI

星界

A Musical Isotope based on Isekaijoucho, later extended from singing into speech synthesis. [1] [2] [3] [4]

Format
Voicebank singers
Performance
Voice synthesis
Project market
Japan
First release / debut
Unconfirmed
Organization / project
KAMITSUBAKI STUDIO / Musical Isotopes

Biography

SEKAI adapts Isekaijoucho’s voice into a CeVIO AI singing library that creators use to make songs. Learning vocal characteristics for a voicebank is a separate production process from the originating singer’s own performances.

Initial sales took place at Niconico Chokaigi in April 2022; the announcement distinguished event advance sales from subsequent delivery. A VOICEPEAK TALK EXTENSION followed in December 2023, adding text-to-speech alongside the character’s singing product.

[1] [2] [3] [4]

Milestones

  1. Advance sales begin at Niconico Chokaigi [2] [3]
  2. VOICEPEAK TALK EXTENSION released [4]

Sources

  1. Musical Isotopes — SEKAIAccessed 2026-10-20
  2. CeVIO — SEKAI reservations and event advance salesAccessed 2026-10-20
  3. CeVIO AI third-party product catalogueAccessed 2026-10-20
  4. KAMITSUBAKI — SEKAI TALK EXTENSION releaseAccessed 2026-10-20

April 29, 2022 is the documented advance-sale milestone, not a delivery date for every channel. Singing and speech products are recorded separately; the earliest character reveal remains unverified.

Updated 2026-10-20