Quake I

"After the chaos of the Doom Wars, the Earth Realm fell into a Dark Ages... not only of technology, but of the human psyche as well. Only through the efforts of the UAC did humanity pull itself out of the depths of its post-apocalyptic environment.

The Vadrigar, meanwhile, attempted once again to exercise their grasp on the Earth Realm...

The UAC, with its new gothic surroundings, began work on "slipgates," transports based on the Martian Gate technology. Devised as a means of moving troops across the globe instantly, the slipgates ran into two difficulties. The first was that soldiers who entered the slipgates often returned insane, rewired for carnage and shooting anything that moved. The second, and much more important, was that an otherworldly being known as Quake was using the slipgates to bring his own troops to the Earth Realm. A task force was assembled, in hopes of tracking Quake to his home dimension and defeating him.

They were too late.

Quake struck first, invading Slipgate Central with his forces. The base was completely destroyed. Only one soldier survived of the original task force. Undaunted, he continued onward, determined to defeat Quake's minions. He travelled through four dimensions and defeated Quake's second-in-command, Shub-Niggurath, before being stolen away to the Arenas Eternal.

When the split began among the gladiators, the Slipgaters that survived formed under one banner. Unlike most factions, they wished very little of actual changes. They did not wish to change the Arena so much as receive recognition of their influence on it. The environments and weaponry of the Arenas Eternal bore more semblance to their era than any moment before or after. Others fought before, and fought after... but the Slipgaters feel they fought best."

Quake II

 "The victory over Shub-Niggurath and the minions of Quake was enough to help pull the Earth Realm out of its mental stupor. A pattern of rebirth and regrowth ensued, bringing the planet into a period of wealth it had not seen since before the Doom Wars. The UAC bolstered such efforts through a massive space exploration program.

Already defeated thrice before, the Vadrigar prepared one final assault on the Earth Realm. They had attempted to defeat humanity with themselves, with races similar to their own, and with beings far beyond the Earth Realm's comprehension. This time around, they hoped to bring humanity's own technology against them.

The joy humanity shared for the new space exploration turned to horror when those same explorations upturned a new threat. A new race, the Strogg, had revealed themselves, attacking any who approached. A cyborg race, the Strogg began pursuing humanity... both for spare parts, and for food.

The Strogg had perfected a wormhole technology, allowing them to send ships directly to Earth to assault all of mankind. Enraged, the Earth forces unified together to use these wormholes to assault the Strogg directly, on their homeworld of Stroggos.

And so, every capable soldier joined under the UAC banner for Operation CounterStrike. Three gigantic motherships entered the wormhole, and came out in orbit over Stroggos. These ships then deployed thousands of soldiers, who began their D-day invasion.

It was a slaughter. The Strogg were prepared, and an EMP device set up in the capitol city of Cerberon blew three-fourths of the forces out of the sky the instant they entered the atmosphere. The remaining troops, scattered, were easily picked off by the organized Strogg forces.

Less than five percent of the troops survived the initial attack. Of those, a handful were able to penetrate the Strogg forces, disabling systems to allow a second airstrike to destroy the city. These forces worked their way into the heart of the military base, assassinating the Strogg's leader, the Makron.

Many of these souls were never rescued from Stroggos' surface. They were, however, snatched quite handily for the Arenas Eternal. These soldiers, left to fend for themselves, unified once more when the tumult began within the Arenas. Much like the Slipgaters, they wished to unite for the sake of identity. Of course, they had demands of their own. As Grunt simply stated, "Gimme back a REAL BFG."