The participants in the R&D wars were on one side Hereti-Corp who joined with other companies to become 4U Corporation. They fought the alliance of NoFun Corporation and Crushestro Inc. whose army consisted of NoFun mutants armed with advanced Crushestro weapons. These fighters were able to absorp defeated enemies into their ranks, and have been known to sweep all of asia in a month.
Remnants of this army is referred to as Outsiders.
It seems that many dimensions parallel to the Dimension of Rain have also had R&D Wars, and in some of these the NoFun/Crushestro alliance won. In the comics main dimension the R&D Wars have not yet broken out, but the corporations are getting increasingly hostile.