Inferno: The Second Coming

Death comes for everyone; and you're no exception.

You've cleaned them out from Phobos, from Deimos. You had slain them
in their own reality, hell. You've even eradicated them from Earth
itself. For a while, you thought they were gone for good.

You thought wrong.

The UAC knew better than to tamper with the gateways. That wasn't the problem.
The problem was that a mysterious satanic cult, known as the 'Minions of The
Mastermind', had broken into one of UAC's main research complexes, at Groom
Lake, Nevada (otherwise known as Area 51). Investgators are still trying to
figure out how they broke into the seemingly impenatrable base, let alone how
they knew about the gate, or worse, how to operate it. It wasn't possible to
investigate the area because of the demons that had come through the newly
opened gate. The only real information anyone had about what happened was from
a scientist who had reached a survaillance camera:

     "God I hope someone gets this. Th-they stormed in here yelling a-about
     the int-terdimensional gateway we abandoned years ago. W-we told them
     it was inoperable. They wouldn't list-ten." (Pounding at the door behind
     him) "We had no other choice but to lead them to it. At first we thought
     i-it was just some publicity stunt. We were dead wrong. It's deja-vu all
     over again. Hell On Earth has retu--- AAAAAAh.. ..AAAAAAAAAAAH" (Bull
     demons storm through and rip the scientist to gory pieces)

Because of your previous victories you were the first person the DOD (Department
Of Defense) called. When you saw the tape you knew what to do.

You barely got past the demons guarding the gate to the complex. You were able to
covertly sneak into the complex via the ventilation system. As you hid behind the
grating inside a vent shaft you saw two gaurds in front of the gateway. They would
be quite formidable opponents, being Barons of Hell. There wasn't anything else
in the room though. The BOHs were soon reduced to cinders by your new Ion rifle.
You stepped up towards the demonic portal to feel a sudden sense of dread no mortal
should feel. But you soon shrugged off this felling; you had looked into the face
of pure evil before. You had been to the place off limits to mortal beings. You knew
no fear.

Lock and Load, marine. Inferno is about to get hotter.