Guardian of Hell

"My Guardian will destroy you!"

- Betruger

The Guardian of Hell (or simply The Guardian) is the second boss in Doom 3. This monster is seen exclusively when the player reaches the end of the Hell level. It guards the Soul Cube, which the player must defeat the giant beast to obtain it.

Appearance
This monster takes the form of a gigantic (roughly 20 feet tall) vaguely bipedal crocodilian beast. It has grey skin, a large muscular body, a volcanic formation across its back, two hands that look like mace heads made from magma with cracks in them, and hooved feet. It has long tail that ends with a spiked ball. Its head resembles a reptile-like skull and sports two long horns that bend and curl downwards.

Combat characteristics
"Destroy the Seekers, and the Guardian becomes vulnerable."

- The Soul Cube

The Guardian of Hell is blind due to its age; what remains of its eyes are shallow pits. In order to 'see,' It summons smaller creatures called Seekers, as spotters. They float in the air above and ahead of the Guardian, serving as mobile searchlights. Only three can be active at a time, but when one of the seekers spots you, it directs the Guardian to charge at your location, giving out a loud chirping noise.

The Guardian's primary attacks consist of punching with its large fists and pounding on the ground, emitting fireballs that burst from the Guardian in all eight directions. It will also charge at the player and attack with it's horns if close by.

The Guardian's tough hide renders it invulnerable to all forms of weapons fire. The only way to harm and kill this goliath is to take out its Seekers. When all the Seekers are dead, the Guardian stops and forms a blue sphere above its head, which generates more Seekers. This blue sphere reveals a glowing energy orb in the Guardian's back; this orb is the beast's only weakness. However, this weakness will only show itself for 5 seconds. It will also pound the ground repeatedly during this process, sending waves of fireballs around it to stop the player from getting too close.

Strategy
Killing the three Seekers forces the Guardian to generate more, revealing its vulnerable spot: a glowing orb of energy in an opening of the Guardian's back. Shooting this orb is the only way to kill the Guardian. As you fight the Guardian, the Soul Cube will inform you of this weakness.

The Guardian is relatively easy to kill if you can manage to avoid the fireballs. Kill the seekers with the plasma gun or the rocket launcher, and when the glowing energy orb appears, unload your chaingun or rockets into it. This should kill the beast in 4 rounds (3 if you aim well).

It is also possible (although difficult) to kill the monster using 2 charged BFG shots. For those seeking a quick end, a single, well-placed shot from the BFG can destroy all of the Seekers at once, rendering the Guardian vulnerable much quicker. The BFG is therefore actually more useful against the Seekers than against the Guardian itself.

After killing the beast, the Soul Cube is released.

Unlike most other demons, the Guardian's body doesn't dissolve.

Resurrection of Evil
In Resurrection of Evil, the head of the Guardian is engraved on some stone tablets. This could mean that either the Guardian left Hell to assist in the invasion, some of Mars' civilization saw it in Hell, there may be more than one Guardian, or it was simply aesthetically pleasing to the game's designers.

The Lost Mission
A somewhat modified version of the Guardian appears as the final boss of The Lost Mission mini-expansion campaign included with the BFG Edition.

It appears as the final enemy guarding the captured teleportation unit located deep inside Hell. This Guardian uses similar attacks as the regular version, but is not blind and so doesn't need Seekers. Instead he lobs a series of mortar-like energy balls from his back.

He can be harmed by regular weapons fire, and does not need to be hit in a weakspot. However, he has significantly more health than the regular version, being able to withstand about 30 rockets or 3 or 4 fully charged shots from the BFG 9000 before falling (which would make his health on par with that of the Cyberdemon and Maledict, the final bosses of the game's other campaigns). Additionally, hitscan projectile hits on him only seem to register during and immediately after one of his attacks.

It could be speculated this may be a younger Guardian, as it hasn't lost its sight with age and is tougher than its elder variant.

Trivia

 * The designers commented in the Making of Doom 3 book that the Guardian was created with the idea of a pre-human Hell during the prehistoric age, and it was something that dinosaurs feared.
 * A prominent promotional artwork image for the Doom 3 BFG Edition features the Guardian of Hell looming in the background, while the Bravo team survivor is engaged in a combat pose in the foreground.
 * With only 800 hit points, the Guardian is the weakest boss in the entire game. It makes up for this by being impervious to weapon fire (apart from its weak spot).
 * The Guardian in The Lost Mission has 5,000 health, more than any enemy in the original campaign and tied with the Berserk Hunter for having the third highest amount of health of any boss in the game (just behind the Invulnerability Hunter and the Maledict).