Initially, the lawsuit only included Oculus as the defendant when it was filed in 2014.
Facebook was later added to the mix after it went on with its $2.3 billion purchase of Oculus despite the fact that its company executives are accused of stealing tech from ZeniMax.
According to ZeniMax, their VR tech was stolen by Oculus after the latter pirated a handful of key employees working on VR projects from their subsidiary game developer company.
This has been denied by Oculus in a statement issued last week.
“Oculus and its founders have invested a wealth of time and money in VR because we believe it can fundamentally transform the way people interact and communicate. We're disappointed that another company is using wasteful litigation to attempt to take credit for technology that it did not have the vision, expertise, or patience to build.”
Facebook and Oculus has been recently making improvements to its VR headset. Last October, Zuckerberg himself conducted a demo of the new Oculus VR avatars.