When GRIN shut its doors earlier this month, the company expressed disappointment the world would never see the "masterpiece" project it was currently working on. Thanks to some snooping by superannuation, however, a number of resumes by former GRIN employees point towards a Final Fantasy-based project for Square Enix dubbed Fortress.
"During 2009 I’ve been working on the preproduction for an unannounced, and now canceled project with the production name 'Fortress' for Square Enix," reads one resume.
Fortress was most likely a temporary name. The game was never announced, but there's some concept art from the project. Some have mused it would have been an action-oriented Final Fantasy. Some more of that art is featured below.