The father of Final Fantasy is founding (another) game studio
Here's a factoid: Hironobu Sakaguchi, lead designer of the original Final Fantasy and design lead for many of the games that would follow under that title, is only 53. If he seems like a wizened old grandfather dispensing sagely wisdom in his public appearances, it's only because he's put in several lifetimes worth of work into the many (many, many) shipped titles under his belt.
Here's another factoid: Sakaguchi hasn't been part of Square (now Square Enix) since 2003. He has actually been out of Square longer than Final Fantasy XV has been in development, a significant milestone, all considering. In a recent interview with Kotaku, FFXV director Hajime Tabata said that it wasn't until Sakaguchi recently sat down and played the "Episode Duscae" demo that he acknowledged the work Square Enix was doing with the long-delayed project: "That's what caused him to come around on our side and support us -- it convinced him. He told me that he really felt like Final Fantasy has moved on to the next generation."
Sakaguchi's been plenty busy with his own projects since leaving Square, of course. In 2004 he founded Mistwalker, a "co-development" studio which designs story and audio in-house and then contracts out the rest of development out to other companies. Under this label Sakaguchi's shipped 10 titles to date, most of them role-playing games featuring past Square collaborators such as Akira Toriyama and Nobuo Uematsu. At present, Mistwalker's collaborating with Bravely Default developer Silicon Studio on what is most likely another classically-styled JRPG.
It would appear Sakaguchi hasn't quite had his fill of the games industry yet, however: he's just announced the founding of a third studio, as yet unnamed, but likely to be monikered Dawnwalker -- a sister company to Mistwalker, focused on those aspects of game development Mistwalker has tended to outsource.
Details (in English-language publications) are scarce at the moment, but just looking at the cards on the table, this seems to point to some down-the-line merger between the two -walker companies, doesn't it? The two of them together field most of the aspects of pre-production and production associated with game development, so it would make sense for Sakaguchi's two studios to develop together, in-house, than each of them contract with separate companies -- but I'm not a businessperson in the Japanese games industry, so all I can do is speculate. At the moment, Sakaguchi's maybe-Dawnwalker studio is still staffing up for its Roppongi, Tokyo office and no titles have yet been announced.
Below: the archived livestream where Sakaguchi announces the new studio.
CORRECTION: A previous version of this article referred to Sakaguchi's role as programmer, rather than designer.