The Guardian is the massive Dragon-like creature deep in the inner depths of
hell. It attacks both with a wide spread of fireballs, and a vicious mauling
attack if it gets close enough. Unfortunately, it's thick hide is COMPLETELY
impervious to all weaponry, so a full frontal assault is totally out of the
question. No, the key to destroying the Guardian it it's minions, the Seekers,
which it releases to assist in tracking you during the battle. In fact, the
soulcube itself makes it a point to tell you this during the battle, in case
you don't figure it out.
The seekers themselves (which look like smaller versions of the final boss in
Half-Life, for those of you who played it) do not attack you at all, they
simply float around, tracking you with their spotlights so the Guardian can
find you. They have medium damage resistance, and float pretty quickly, so
start taking them out with the chaingun or machinegun as soon as you see them
(if you have good aim you can use the plasma gun or rocket launcher, but
they're not recommended as their projectiles travel slower than bullets and
have a greater potential to miss) while keeping your distance from the guardian
itself and dodging it's attacks.
Once you've killed them (I think there's about 5) the guardian will stop to
generate more, and that's your cue to attack. While generating seekers, the
Guardian will have a glowing energy ball above it, that you should immediately
target with your most powerful weapons. Use rockets or BFG (if you have any
ammo left), or plasma as a last resort. Should you run low on ammo, there is
ammunition for various weaponry scattered about the battlefield, mostly
concentrated around the four big rock-obstacle things. You will need to repeat
the process a few times before you win this battle- just avoid the Guardian,
destroy the seekers, shoot the glowing sphere, rinse and repeat as necessary.
