Doom Roguelike Enemy Analysis: Hell Knight

HP: 50

Protection: 1

Ranged Accuracy: +6

Melee Accuracy: +6

Ranged Damage: 2d6 Plasma

Blast radius: 1

Melee Damage: 1d3 (+6) Melee

Speed: 110%

Inventory: Nothing

Experience: 128

Danger: 6

Minimum floor: 9/6/3

Maximum floor: 15

Experience per Danger: 21.33

Can open doors, equip Armor, and pick up and use Medpacks, Phase Devices, and Homing Phase Devices. Has 50% Acid resistance.

Evasion: Base of 50%, +5% per tile of distance, making for a maximum of 90%

Attack chance: 40%

One of the biggest ways higher difficulties are nastier is moving these guys earlier. On I'm Too Young To Die, they can't show up until you're done with Phobos, ie until you're past the first third. On Ultraviolence and Nightmare! these guys can jump you on the second floor that uses random floor generation! (In the context of a standard run)

Hell Knights themselves are both straightforwardly a big jump over eg Imps (4 times the HP, more damage, more Accuracy, has built-in Protection...), but are also pretty nasty in several not-so-obvious ways.

First of all is that they're the earliest user of Plasma damage. This is particularly nasty for a player going in 'blind' (Why would you expect that Imps and Hell Knights are flinging totally different fireballs?), but even when you know about it to account for it... it still means that eg wearing Green Armor is worse than being naked! (Because you suffer the slight movement speed penalty, but don't benefit from its 1 Protection) Their small damage advantage over an Imp (2d5 on Imps vs 2d6 on Hell Knights) tends to be a bigger gap than you might assume as a result. (eg if an Imp rolls 5 damage and a Hell Knight 6 damage when you're wearing Green Armor, the Hell Knight will actually hit 50% harder than the Imp, not 20%!)

Second is their modest Speed advantage. 110% Energy generation is high enough that Hell Knights have pretty decent odds of getting a cheap shot in through an unexpected double-move; you move forward and get hit twice, or you pass a turn and a Hell Knight walks into view and immediately attacks before you get a turn, or a Hell Knight double-moves right past the Perfect Spot To Start Shooting It... there's a lot of ways it can be nasty, and it will come up way more regularly than an Imp doing so with its 105% Energy generation. That 'you walk forward and get immediately attacked twice' scenario is especially more likely to happen than a cursory inspection of the numbers suggests, since most Armors impose a movement speed penalty: even just wearing a Green Armor means the odds of a Hell Knight getting to attack twice are more like 15%. (Unless you're a Scout, have Hellrunner, are wearing speed-enhancing Boots, or are currently Berserking)

Third is their astoundingly high Accuracy. The highest Ranged Accuracy we've covered prior to the Hell Knight is +4 on Cacodemons and Former Humans. (Via their Pistols) Above I'm Too Young To Die, a Hell Knight has a 90~% chance to land its shot if firing at max range... unless you're on Ultraviolence or Nightmare! In that case, its hit chance is at max! It's easy get used to the semi-regular misses of lower-end enemies and just expect a Hell Knight is going to miss some of its shots, but if you're not leveraging the Dodge mechanic... uh, no. You should just treat it as Always Hitting, because it's pretty close to true. So a Hell Knight's true DPS is even higher over an Imp than the numbers suggest, and indeed a Hell Knight is on average more lethal than a Cacodemon even though their shots have identical damage, damage type, and splash radius.

Fourth is that, like Cacodemons, Hell Knights actually hit harder in melee on average than at range. Stepping into reach in an attempt to lower damage taken is basically always going to backfire outside the partial exception of Angel of Max Carnage runs. This can be very jarring if you've gotten used to the idea that humanoid ranged attackers can often be neutered by standing next to them: surprise! Not these ones!

Fifth is their Acid resistance, which is atypical and easy to forget about. On higher difficulties especially, it's pretty easy to end up shoving a Hell Knight into an Acid river, write it off as a dead goatman walking, and then take an unnecessarily large amount of damage from it because it took a lot longer to die than you intuitively expected. Same with overestimating Acid Barrel ability to hurt them, and of course so too the Acid Spitter.

Sixth is their ability to equip and use Armor and single-use items. It might seem strange to include this in the 'nasty in not-so-obvious ways', but it's not necessarily intuitively obvious how their strong statline makes this quality way nastier than with the basic zombie enemies.

Medpacks are pretty straightforward. Medpacks are percentage heals, so the Hell Knight's higher base HP means they add more HP per use: a Former Sergeant using a Small Medpack gets 5 HP, while a Hell Knight gets 15 HP, three times as much. Furthermore, a Hell Knight's greater durability makes it much more likely to get the chance to heal: a Former Sergeant is often pasted in one hit once you're done relying on a single basic Pistol, and so can scoop up three Medpacks and not get to eat any of them, whereas a Hell Knight is so tough that even builds with great DPS overall will pretty regularly end up with a Hell Knight below 50% HP that then lives long enough for it to get a turn and eat the Medpack. A Hell Knight carrying three Medpacks has pretty good odds of eating all of them before it dies -exacerbated by its Speed advantage.

Less obvious or intuitive is Armors. It's easy enough to understand that eg a Former Sergeant scooping up a Red Armor may still be splattered in one shot, deriving zero functional benefit, where a Hell Knight's greater durability makes it almost impossible for them equipping Armor to do nothing, but there's two less obvious wrinkles. First is Protection stacking: the more Protection one has, the greater the proportional impact of further points, up until you ram into the 'attacks normally must do at least 1 damage' limit. Since Hell Knights have a built-in point of Protection, equipping an Armor often protects them a lot more than you might intuitively expect.

The particularly non-obvious point is Armor shredding. I've laid out how Armor durability is based on raw HP lost, but this isn't communicated in-game at all and is hidden in practice by the game never displaying raw HP anywhere (Doomguy's HP is rendered as a percentage display, while enemies get vague verbal descriptions like 'scratched'), so in playing the game it's not going to be obvious what to expect to happen when you kill different enemies equipping Armors. Since it is based on raw HP lost, though... enemies with higher raw HP equipping Armors invariably result in those Armors losing more durability in the process of killing that enemy.

Thus, when a Former Human picks up a Red Armor, not only is it entirely possible you'll one-shot it anyway, but the Red Armor itself will have only lost a small amount of durability, whereas a Hell Knight equipping a Red Armor will be made much harder to kill and the Armor will be horrifically shredded when it drops... or it might not drop at all, instead being completely destroyed, if the Hell Knight is also carrying Medpacks to stack on even more HP to tear through. When wearing the Red Armor makes it much harder to kill it before it can use those Medpacks!

So overall, Hell Knights being allowed to use some of Doomguy's equipment is way nastier of a quality on them than it is on the basic zombie enemies, even though they don't have a superior version of that capability. (That is, it's not like Hell Knights have more slots to store equipment in, or anything like that)

Even their ability to use Phase Devices ends up more functionally relevant. It won't come up very often, but a Hell Knight is not only way more likely to get a chance to use a Phase Device, but if using the Phase Device then results in it getting to scoop up a Medpack and/or Armor, this happening is way more consequential than if a Former Captain zaps itself away and then finds and uses a Small Medpack.

Indeed, I... kind of wish Hell Knights couldn't equip gear. I'm generally pretty fond of games incorporating this kind of player/enemy equivalence, where powerups and whatnot 'really exist' and can be used by everybody in the game world, but Hell Knights (And Barons of Hell...) being able to scoop up and use items ends up this wonky bit of design jank, where having such enemies spawn nearby such things tends to unavoidably take those items away from the player and randomly and invisibly substantially upgrade those enemies. It was a bit of a relief when Jupiter Hell didn't seem to have any enemies capable of scooping up and using player gear. (It's possible I just haven't run across this as a mechanic: I seriously haven't played Jupiter Hell much as of this writing)

Anyway, overall Hell Knights work very well as a well-rounded nasty upgrade over early-game enemies, just... with some rough edges from how much of what makes them threatening is not at all clear just from playing the game. Among other points, they're one of the earliest enemies where by far the best responses are 1: try to Dodge and 2: corner-shoot, and it's easy to go a long time unclear what (if anything) one is doing wrong that early Ultraviolence Hell Knights keep casually killing you, or at least costing you too much Armor and Medpacks in the process of defeating them.

And honestly, most of the jank would be smoothed out by making the game itself a little less opaque. (And/or a bit less willing to do things like small Speed deviations: I suspect very few players have figured out entirely on their own that Hell Knights are very slightly faster than base and that's why they sometimes double-shoot you for no clear reason and whatnot)

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Next time, we cover Barons of Hell.

See you then.