Doom Roguelike Enemy Analysis: Mancubus

HP: 60

Protection: 2

Ranged Accuracy: +3

Melee Accuracy: +3

Ranged Damage: 4d6 Fire (Per projectile)

Blast Radius: 1

Melee Damage: 1d3 (+8) Melee

Speed: 80%

Inventory: Rocket ammo*3

Experience: 452

Danger: 12

Minimum floor: 15/12/9

Maximum floor: Infinite

Experience per Danger: 37.66

Can open doors. Never succeeds against Doomguy's Dodge check, and thus usually targets Doomguy's previous position. Fires 3 projectiles per attack, one aimed at the target tile and the other two aimed to the sides. Additionally, anytime it fires, normally its following turn will be spent on a second volley aimed at the same tile as the first volley, even if the Mancubus can't see Doomguy anymore.

Attack chance: 50%

Behold! The enemy that can kill Doomguy from max HP with a single attack if Doomguy has inadequate defenses and bad luck!

Seriously. A volley rolling max damage on every shot is 72 damage. Prior to 0.9.9.8 adding energy resistances to Marines, even a Marine would die instantly to that. (With 0.9.9.8 adding energy resistances, they'll barely survive) That's very unlikely to happen, of course, but it's still a useful illustration of how dangerous Mancubi are, and how important it is to have Fireproof Armor or the like by the time they're showing up. (Which on Ultraviolence can be as early as the very first floor of Deimos!)

Now, of course, part of why it's unlikely to happen is the point I've covered several times before on other topics; that conceptually-simultaneous actions are resolved sequentially by Doom Roguelike. Thus, even if you're positioned so a Mancubus firing looks like it hits you with all three of its shots, the first shot to hit you may well knock you out of position so you're not caught by the other shots.

Mind, it's also possible to get hit by two or (improbably) all three shots in a situation where simultaneous resolution would only get you hit by one shot, by virtue of the knockback from shots sending you into follow-up shots. With how hard Mancubi hit, their shots can in fact knock Doomguy up to 4 tiles. (Though only if they roll literally max damage... but 3 tiles is pretty probable) As such, even when Doomguy is so far from a Mancubus that its shots are very far apart, they can spike out very alarming amounts of damage depending on how things go.

I'm actually not 100% sure what order Mancubi shots are internally resolved at. I'm mostly-confident the middle shot is fired first, and from there I want to say the left shot is fired before the right shot, but it's entirely possible I've misunderstood my experiences. For one thing, Mancubi are tied with Revenants for 'enemies I heavily prefer to just not give opportunities to attack at all'.

I should point out that Mancubi always failing the Dodge check when firing on Doomguy is one of the subtler flaws with Dodgemaster, as Dodgemaster is still 'expended' on a Mancubus attack. As such, if a Mancubus ends up being the first to fire out of a group of enemies, Dodgemaster does literally nothing!

Anyway, Mancubi doing follow-up fire is one of the more easily misunderstood special mechanics of the game, and also one of the biggest reasons they're so deadly. A Revenant that knocks Doomguy out of view has to run to get him back in sight to resume shooting. A Mancubus that does so will fire blindly and be pretty likely to hit Doomguy -for one thing, as far as I can tell enemies don't suffer the 'past line of sight, shots have a separate 50% chance to miss no matter what' issue that Doomguy does. For another, if Doomguy has ended up near a wall, Doomguy can't be saved by an Accuracy check failing!

Since Mancubi hit so hard, unless Doomguy has serious defenses it's very, very easy to have a single Mancubus take Doomguy from full HP to dead off one sighting.

Anyway, I was saying the follow-up fire is easy to misunderstand, and there's a couple big reasons for this. First, while I haven't gotten to any of them yet, there's a few enemies that can see and shoot at Doomguy from beyond standard line of sight; it's not necessarily obvious that a Mancubus firing from beyond Doomguy's sight isn't simply another example of this.

Second and more significant, the follow-up fire can be interrupted, but the rules on this are fiddly and not at all intuitive. Specifically, knocking a Mancubus out of line of sight will interrupt its follow-up fire routine... if Doomguy is not in the Mancubus' sight when it next gets a turn. That is, if Doomguy uses a Shotgun to knock a Mancubus out of sight after it's shot at him once, then steps right back into view before it gets its next turn, the Mancubus will engage its follow-up routine and fire wherever it last shot, even if Doomguy is several tiles away from that spot (Thanks to the knockback, quite likely), but if Doomguy is just slow enough to get back into view that the Mancubus gets a turn before he's in sight again, it will start a new first volley when it gets a turn with Doomguy in sight.

This is all very strange, and it's not necessarily obvious the difference between 'Mancubus failing the Dodge check' vs 'Mancubus using its follow-up routine'. I frankly only figured it out by virtue of it clearly operating under the same logic as Archvile channeled attacks, where the strangeness is still confusing and unintuitive but is less obscured. (Though talking about Archvile attacks is for next post)

Not helping is that Mancubi are so prone to friendly fire (It's not shocking for a Mancubus to hurt itself) and so good at applying knockback. A learning player can easily have no idea the follow-up fire behavior is technically 100% consistent, because a Mancubus being knocked out of position by friendly fire works just as well to interrupt the routine as being knocked out of position by Doomguy's fire, and this happening can be totally invisible. Also not helping is that Mancubi are moderately slow, and this itself isn't super-obvious in regular play; a player may think a Mancubus failed to do follow-up fire, not realizing the Mancubus just hasn't gotten its next turn yet, since it takes them about 25% longer than base Speed enemies to get to their next turn.

All those special mechanics aside...

Well, I already covered how lethal Mancubi are, and it's worth emphasizing anew that even though their Accuracy is poor by the standards of late-game enemies, their splash damage and spread shot behavior means it's easily possible to be fired on in a situation where damage is guaranteed. I should also emphasize that Mancubi are very tough, with literally the same defensive statline as a Baron of Hell: they don't have Acid resistance (Or any other resistance, for that matter), and thankfully can't equip Armor or use Medpacks, but still, trying to survive by deleting them before they attack requires an outrageous capacity to output a lot of damage in a short period of time. This is possible, to be clear, but plenty of runs won't have that kind of firepower by the time Mancubi first enter rotation.

I should also point out that getting into melee with them, though generally a lot less dangerous than letting them blast you with their rockets, is still fairly dangerous. +8 damage with +3 Accuracy means they hit over 80% of the time for 9-11 damage, which is pretty painful! If you've got something like Cerberus Armor or Fireproof Red Armor equipped, closing to melee may actually make them hurt Doomguy more than letting them blast him with rockets.

It's also worth emphasizing that Mancubi are the single enemy most prone to smashing walls and annihilating items. They do enough damage per shot it's not surprising for a shot to instantly vaporize a wall segment, and their spread-shot behavior can easily result in lots of holes being blasted. Mancubi are generally the most important enemy to maintain an awareness of what's behind you; it's easy to die not because a Mancubus murdered Doomguy but because it opening fire blasted the walls behind Doomguy and a bunch of Arachnotrons jumped on the opportunity to pour damage on. Same for losing Supercharges, Invulnerability Globes, etc, because you approached at a poorly-considered angle.

On the plus side, Mancubi sounds are completely unique, so you generally get warning that one is about before it starts vaporizing everything.

Oh, and Mancubi are another enemy that got a new sprite in 0.9.9.8, with the new one on the right up above. I don't get this sprite change. The old one is great, and the new one is only different by raising the arms to make the legs more visible, which is actually less faithful to the classic Mancubus sprites, where they do tend to have their arms basically dragging along the ground. It's a weird decision.

On a different note, I'm curious why Mancubi do triple-shots. The 'fire three shots twice' behavior arrives at the same total shot count as classic Doom Mancubi, but in classic Doom they did so with three volleys of two. Was it just easier to code the triple shot? Did the devs not like a Mancubus spending three turns in a row on a single attack sequence? Were they focused on recreating the thing where the overall spread goes three ways in classic Mancubi? Something else entirely?

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Next time, we cover the V in the Dread VMR: Archviles.

See you then.