Hell Knight/Doom 3

The Hell Knight is a powerful demon in Doom 3.

Physical appearance
The Hell Knight is huge and very muscular. An in-game examination of its spine indicates it has a massive skeleton. It has no visible nose, and its deformed ears resemble a human's, fused to the sides of its head. Its obscure eyes are very small and black, located on the sides of the head just above the mouth. It is easily the largest non-boss enemy in the game. Assuming the Marine is 6 feet (1.8m) tall, the Hell Knight stands about 10 feet (3 meters) tall.

In Hell, Hell Knights show a different appearance from those on Mars. Their skin is greyish-green and some parts, such as the mouth, upper chest, hands and feet, are red, possibly soaked with blood. They are covered with scars and demonic runes, and have a pentagram on their forehead.

While the classic Hell Knight has horns and hooves, being meant to resemble a satyr or minotaur, the Doom 3 Hell Knight somewhat resembles a huge muscular skeleton or an alien. The head of the Doom 3 incarnation of the Knight is somewhat similar to the Shambler from the first Quake.

Two of these massive monsters make their introduction in a cutscene (obviously mirroring the debut of the first two Barons of Hell as sub-bosses of Doom 's first episode) in which the marine arrives at a teleportation room where he witnesses the portal to Hell being opened under Malcolm Betruger's supervision. A biosuit-clad scientist emerges from it, followed by a huge Hell Knight right behind him. The scientist pleads for his life, but the Knight grabs and throws him violently against the machinery of one of the portal generators, presumably killing him; a second Hell Knight comes out from the portal and then both monsters charge towards the marine.

Combat characteristics
The Hell Knight's attacks are similar to those of the Imp's: it throws greenish blue fireballs at long range and substitutes to clawing attacks at close range. However, it lacks the ability to leap and its clawing attacks are a lot slower, as the lag to initiate their attack is around 2-3 seconds. To make up for it's lack of agility like the Imp, it also consists of a biting attack, which gives it a farther reach than it's clawing, although like it's clawing, it suffers from the same lag duration to initiate it. The green plasma balls it throws are much larger, more powerful, and have a wider area of effect.

Tactical analysis
The Doom 3 Hell Knight is actually tougher than the original Hell Knight, having almost as many hitpoints as the original Baron of Hell. The Doom 3 Hell Knight takes six direct rocket hits to kill, while the Baron of Hell in the original version usually took five (depending on the random damage rolls). It is probably for this reason that there is no Baron of Hell in Doom 3; the Hell Knight fits the role. Essentially, rather than being the new version of its classic namesake, the Doom 3 Hell Knight is the reinterpretation of the original Baron of Hell.

it is strongly recommended to take out Hell Knights from range. The Rocket Launcher, Plasma Gun, Chain Gun, are very effective weapons to take them out. It can take close to a full magazine of the Chain Gun and Plasma Gun to kill one, but their large stature and slow speed makes targeting headshots easier, in which fewer shots are needed to finish them off. If the situation permits, the Soul Cube and BFG is an excellent choice.

The Hell Knight, despite being deadly, is also quite slow and avoidable with it's attacks. You can get up close range and unleash your Shotgun couple of times while actively backing away to avoid their clawing attacks. However, be careful as they can also bite, which allows them to hit you further than it's claws.

At range, it is a very bad idea to retreat from one when the monster is about to throw a fireball, as a direct hit can do grievous damage. Fortunately, its fireballs are very easy to dodge, as the Hell Knight's height means they are launched from farther up, making it possible to literally run under them. However, take caution to not get yourself cornered in enclosed spaces as their fireballs can do significantly high damage from the splash damage.

The expansion pack and the additional content of the BFG edition introduces two new weapons to even out the odds against the Hell Knight. The Grabber is a relatively effective weapon, however it requires 5 direct volleys from and back at the Hell Knight to vanquish it. The super shotgun is also relatively effective, provided the player has sufficient space to keep dodging, firing and reloading.

UAC research notes
These notes can be downloaded to the player's PDA during the course of the game:

Specimen 31 - Hellknight (partial)

''The cranial mass of this bipedal specimen indicates that it is one of the largest creatures inhabiting the site. Overpowering its prey with sheer might, the Hellknight is one of the most ferocious predators known to our researchers. Like the imp, this creature is able to defend itself at long-range with thrown plasma projectiles.''

Doom Resurrection
The Hell Knight is a boss in Doom Resurrection in the fourth chapter, inside the Delta Labs. Its only attack is to throw green energy balls at the player, which can cause quite a bit of damage. They can be dodged like a usual Imp's energy ball. After draining its energy bar, it will push the player into the hellgate to end up being send to hell.

Trivia

 * The first Hell Knight's appearance was in Delta Labs 4. The portal to hell activates, and two Hell Knights emerge. They also have noticeably more health than the regular Hell Knights fought later in the game, having about 1400 health, compared to 900 health for a standard Hell Knight. This makes the two of them something of a boss encounter, reminiscent of the first bosses in the original Doom, where the player must defeat a pair of Barons of Hell at the end of Knee-Deep in the Dead.
 * The Hell Knight is often said to be the scariest enemy in the game for many reasons. Aside from it's high hitpoints and damage, the beast is one of the tallest enemies in the game. It also has an unsettling visage and growl and makes the screen tremble when it walks.
 * Interestingly, if one uses the noclip cheat, a stream of saliva can be seen running from the Hell Knight's mouth.
 * The Cyberdemon is much larger than a Hell Knight but, interestingly, it does not make the screen shake when it walks.
 * Hell Knight is featured on the cover art of the game.
 * The 2016 version of the Hell Knight’s model is based on the Doom 3 version, though its body has partially exposed body parts in comparison to the Doom 3 one.