Hideo Baba, perhaps best known as a recurring producer for Bandai Namco's Tales series, started up his own game development studio under Square Enix last year. Formed as Studio Istolia, the team's first title is currently known as Project Prelude Rune, and it got a teaser trailer at Sony's PlayStation LineUp Tour earlier today in Japan.
As we've come to expect of Square Enix and its Japanese-developed games, this seems like a very early reveal, but it at least looks the part. It's being crafted using Unreal Engine 4, and it appears to feature a large, explorable world.
And that's all we've got to go on right now. Keep your eyes peeled for more details in the relatively near future.