An elite infantry force of the New Earth Government, the Marines are friendly allies to the Terran Colonial Authority and thus can work together with John Dalton in some of his missions involving the recovery of the Artifact. As Dalton is a former Marine, he knows many serving Marines and understands well how they operate.
Marines have a strong sense of esprit de corps: when a team of Marine commandos was caught attempting to destroy the Minkovsky Dam on Severnaya by Izanagi Ghost Warrior mercenaries, they retreated and were pinned down in the hills overlooking the dam. Despite being outnumbered and outgunned, the surviving Marine commandos refused to surrender, and in response to repeated demands that they do so, shouted, "Come and get us!"
In addition to their extensive capability for planetside operations, Marines serve as the security force aboard UEG military vessels, protecting the ship and crew from hostile boarders. A notable example of this is Commander Hawkins' flagship, the Dorian Gray.
Like most enemies they come in three classes: light, medium, and heavy. Both weapons and armor are affected by these classes, with the Heavy Marines wearing the toughest and physically heaviest combat suits available, but also wielding the most fearsome weapons, like the rocket launcher.
Marines appear in the following missions of Unreal II: Avalon (preface), Sanctuary (mission), Severnaya (mission), Avalon (mission), Dorian Gray (mission).