A recent patent by Square Enix might have given players some indications of what the developer might be preparing for an upcoming title or future series. While it isn't clear if this will be going towards the next Kingdom Hearts or Final Fantasy titles, it does look like the developer and publisher is looking to expand on multiplayer systems.
There is some language that can lend to what exactly Square Enix is looking to develop with this new system, which implies that this might be something intended for a completely new title. However, much of what this could be for is up to speculation and can't be confirmed for certain, especially considering that the developer could be filing this patent for publishing purposes as opposed to development.
The patent itself is focused on building and improving the multiplayer capabilities for consoles with local multiplayer options, connecting via Bluetooth or other short-range connectivity technologies. Some of the figures within the document even show the program working with a system that looks suspiciously like the Nintendo DS, which does have the type of local multiplayer that the patent refers to. This would be a strange choice, considering that Nintendo has essentially ended development on the portable console because the Switch doubles as a mobile system.
One key difference between this system and previous online systems is that not only is it built for short-range communication, but it also seems to focus on there being a primary user that sends data to nearby devices. As opposed to using the usual features with a mutual exchange of data, the idea here would be that a Player 1 can transmit their own inputs to then be represented on the screens of a Player 2. This can allow players to interact with each other in more superficial ways, such as allowing players to fight facsimiles of each other, as opposed to the one to one version found in Square Enix's other multiplayer titles, like Dissidia Final Fantasy.
It still isn't entirely clear what the developer plans to do with this new patent, though it may have to do with Square Enix's recent Voice of Cards trademark. There haven't been any official announcements by the company to imply that either of these are for any game that fans already know about. However, putting these last two filings together, there may be a mobile game on the way, or even a sequel to Final Fantasy Type-0 with multiplayer capabilities, though this is still only up to speculation and will still need confirmation from Square Enix.
Source: uspto.gov