Being functionally equivalent to the Baron of Hell except for having only half as much health, the weaker Hell Knight serves better as a medium-strength monster, falling more quickly to small arms fire such as from the shotgun or chaingun, or offering some resistance without slowing the action down, against heavier weapons.
The Doom II manual describes the Hell Knight as follows: "Tough as a dump truck and nearly as big, these Goliaths are the worst things on two legs since Tyrannosaurus rex". In the manual for the original Doom, this was the description used for the Baron of Hell. The Official DOOM FAQ uses "Slightly easier to kill than our friend the Baron, but appear in larger numbers. " instead. The manual for the early versions of the PlayStation port refers to them as "Knights of Hell".
- In a ZDoom-based source port, if the player is killed by a Hell Knight (monster is credited with delivering the blow that reduces player's health to 0%), one of two obituary messages will be displayed at the top of the screen depending on which attack the hell knight used to kill the player: "[player name] was gutted by a Hell Knight" or "[player name] was splayed by a Hell Knight" for the claw and green fireball attacks respectively.
- The only other difference in the appearances of the Hell Knight and the Baron of Hell besides their skin color is that while Barons have grey horns and hooves, Hell Knights have dark brown ones.
- It is never stated if the Hell Knight is a Baron-in training, a lower caste, a different sub-species or related species, a younger baron or a female Baron of Hell.
In Doom RPG, the baron of hell and the hell knight both belong to the "baron" monster class. There are three variations, identified by color:
- Ogre (green torso, red hands, brown legs)
- Hell knight (brown torso, brown hands, pink legs)
- Baron (pink torso, orange hands, brown legs)
As in the original, the hell knight is not as powerful as the baron, though both are more powerful than the new "ogre" variation. This class of monster is especially weak against attacks from shotguns.
Due to the Hell knight reusing code from the Baron of hell, Hell Knights and Barons cannot be injured by each other and thus cannot infight normally.