IndieDB’s member ‘guedinaot’ is currently working on a free multiplayer fan game based on the Attack on Titan franchise. This game is powered by the Unreal Engine 4, and its latest WIP is available for download (so you can test it yourselves).
According to its description, in this game players will will fight in co-op against hordes of titan.
Guedin’s Attack on Titan Fan Game is still in a really early stage, and hopefully it will not raise any alarms as an official Attack on Titan game is currently being made for PS4 (with it potentially coming to the PC).
Those interested can download the latest WIP build of this game from here.