Production company Straight Up Films list a Thief project in their ‘In Development’ section, and suggest a fifth title in the series is being made. Specifically, they state “a fifth sequel is currently in development to be released in step with this motion picture adaptation.”
If accurate, this is fairly surprising for a number of reasons. The fourth Thief game had a famously troubled development cycle and came out to decidedly mixed reception (as a long-time Looking Glass Studios fan, I think it misunderstood almost everything that made the Thief series memorable). Having another go at a reboot might work, but who would be making this game?
The Straight Up summary doesn’t say. Eidos Montreal would normally be my guess (since they made the last one, and the last couple of Deus Ex games), but that studio has reportedly been moved on to Square Enix’s new Marvel-based projects; leaving Deus Ex in a state of hiatus.
I suppose there’s also the chance that this may be referring to something like another entry in the GO series. Thief GO could probably work reasonably well.
It’s an intriguing story to emerge on the same day that Square Enix appear to be ditching Hitman studio IO Interactive. The latest Hitman game can claim to be one of (if not the) best in the series, but Square apparently wish to sell IO in spite of this. Meanwhile, the most recent Thief game critically flops but winds up with a potential sequel. Strange times in the Square Enix boardroom.