The Japanese magazine, Newtype will be confirming that Isekai no Monogatari, which is a spin-off from the Tenchi Muyo series, is now in production. This spin-off has been in development for close to a decade now, and it’s got the involvement of Masaki Kasjishima, who is the creator of the Tenchi Muyo series, alogn with Dual.
The basic story is that it’s set in an alternative world, which is called Geminar and the countries on this planet have fought endless wars for an endless amount of time. The wars are all fought by replica humanoid Seikishi weapons that were found in some ancient ruins. Kenji Masaki, a 15 year-old half brother of Tenchi Masaki, is summoned to Geminar.
According to Kajishima the premise for this show began a decade ago, and he already had the idea of a half-brother when he created the most recent Tenchi Muyo series, Tenchi Muyo! Ryo-Ohki.
Source: Moon Phase Comments via Anime News Network