Diabolus

A diabolus (pl. diaboli)^[1] is a mechanoid commander added by the Biotech DLC. It drops the signal chip, required to research further mechanitor technology.

Occurrence

You can summon a hostile diabolus with a mechanitor and a powered comms console. Unlike the buildings used to summon the other mechanoid commanders, the console is not consumed in the process. Therefore, summoning one requires the Microelectronics research. However, they are not exclusive to summoning, as strong enough mechanoid raids may feature one or even multiple.

When summoned, it will be accompanied by other mechanoids. The amount of other mechanoids depends on how many times you have summoned a diabolus before, and is independent of wealth, time, or colony progress. Eventually, you'll have to face multiple diaboli at the same time. They will crash down in a ship after a random amount of time ranging from a few in game hours to days. They will not attack immediately, but will instead act like a raid and "prepare" before launching their assault. The maximum size is reached after summoning the diabolus 8 times.

Summoning:

1x Diabolus, 3x militor
1x Diabolus, 4x militor, 2x pikeman
1x Diabolus with heavy shield unit, 7x militor, 2x pikeman, 1x tesseron
2x Diabolus with heavy shield unit, 10x militor, 3x legionary, 1x centurion
2x Diabolus with heavy shield unit, 10x militor, 5x scyther, 3x centipede (gunner)
2x Diabolus with heavy shield unit, 15x militor, 8x pikeman, 4x centipede (gunner), 1x centurion
2x Diabolus with heavy shield unit, 15x militor, 10x lancer, 5x centipede (gunner)
3x Diabolus with heavy shield unit, 15x militor, 10x tesseron, 6x centipede (gunner), 1x centurion

Like the other mechanoid bosses, after being summoned 8 times, the next summon will be the same as wave 3. The wave count is per playthrough, not per colony or map. If the Diabolus is summoned once on one map, summoning another on a second map will bring the second wave. The Archonexus colony reset does reset this progression.

Acquisition

Diaboli can be gestated by a mechanitor at a Large mech gestator once the High mechtech research project has been completed. They require 300 Steel, 300 Plasteel, 2 Signal chips, 1 High subcore and 12 gestation cycles taking 1,800 ticks (30 secs) each to initiate. They take up bandwidth from their linked mechanitor.

Dead, friendly diaboluss can also be resurrected at the large mech gestator using the "Resurrect ultraheavy mechanoid" bill. This requires the corpse of the friendly Diabolus, 150 steel, and 1 gestation cycle taking 1,800 ticks (30 secs) to initiate.

Summary

The diabolus is an ultra-heavy mechanoid. As mechanoids, every diabolus is immune to fire, Flame and Heat damage, and temperature extremes, despite having Comfortable Temperatures defined. They have 100% Toxic Resistance and Toxic Environment Resistance, making them immune to toxic buildup, rot stink and other toxic effects. They do not need to eat, rest, and have no mood. They will be stunned by EMP attacks for a time proportional to the EMP damage inflicted and will "adapt" and rendered immune to further EMP strikes for 2,200 ticks (36.67 secs).

Diaboli have a 60% EMP resistance, meaning they are stunned for 60% less time.

Defeating a hostile diabolus rewards the player with a signal chip regardless of whether they were summoned or came as part of a raid. Studying one is required to research Standard Mechtech, and they can also be used to create various mechanitor gear, or even your own diabolus.

Friendly diaboli recharge in a large mech recharger, creating 25 wastepacks whenever the recharger's waste is filled up.^{[Per recharge?]}

Combat

An enemy diabolus alternates between two long range attacks:

Hellsphere cannon. When using this attack, diabolus will create a red circle around a target. After a 450 ticks (7.5 secs) warmup, it explodes, leaving a large radius of fire. The blast is slightly larger than the visual circle, so err on the side of caution. This attack only has a range of 18.9 tiles, but also has a minimum range of tiles.
- It deals 800 Vaporize damage, increased to 1600 damage against passable structures and 3200 damage against impassable structures. As an explosive, it ignores cover and has 100% accuracy. This checks Heat armor, but has a massive % AP.
- Unlike other ranged weapons, once initialized, it will continue to fire, even if the diabolus is engaged in melee in the meantime. Engaging in melee will prevent future shots being initialized, but will trigger the flame burst discussed below.
Charge blaster turret. This fires a single shot at relatively low damage and is affected by cover, but can do so from a very long range (44.9 tiles). It can also be fired while moving, and has almost no warmup time.

Diaboli have the ability to emit a "fire burst". Over a few seconds,^{[Detail needed]} it surrounds itself in roughly 5.9 tile radius of flammable chemfuel puddles. Once complete, it releases a Flame explosion of the same radius, dealing damage and igniting the puddles.^{[Details needed]} Enemy diaboli will trigger the burst when engaged in melee, even by enemies that are immune to fire like other mechanoids. Friendly diaboli must have their fire burst manually triggered by the player,^[Verify] and have both a 3 second warmup^{[Verify friendly only]} and a 2,700 ticks (1.08 in-game hours) cooldown after use.^{[Verify friendly only]}

An enemy diabolus won't actively try to breach walls, and it will never appear in breacher raids. However, it will destroy buildings and objects, like any raider, if no pawns are accessible.

Analysis

Kiting and spreading out is key to taking out the Diabolus. The biggest threat is by far its Hellsphere cannon, which can instakill almost anyone and anything. For reference, a pawn with the Tough trait, fire resistant gene, and wearing a legendary duster, formal vest / corset, and button down shirt made of devilstrand still has a 28% chance of immediately dying from torso damage. Players should instead prioritize avoiding the shot in any way possible, either by moving pawns out of the way, staying out of range, or by being too close to target with the cannon.

Be extra careful about fire; if not from the diabolus' blasts, then from the wildfires caused by them, or by the tesserons alongside it. Pawns lit on fire can't be controlled, so you can't order them out of the blast range, which is nearly certain to be fatal. Also be wary of the Fleeing Fire mental break, caused by being a child or having the pyrophobia gene. While short, it is still just as dangerous as any mental break with a diabolus. A firefoam pop pack is very helpful.

You should manually move pawns away from the blast radius, always allowing yourself the option to retreat. Split up your pawns, which will allow more of them to focus on shooting instead of running. You can even use your own militors to lure the cannon or flame burst; their range is short enough to justify staying close, anyway. It only has 1 non-flame attack, so even a cleansweeper can stall for some time.

Melee

Melee can be an effective tactic. But with fire vulnerable pawns, it is highly advised to NOT use melee attacks, due to the close-ranged burst. Sufficient fire protection (devilstrand clothing, phoenix armor , impids' fire resistance) can help tank the flames, and your own mechanoids are completely immune to fire. Firefoam makes your organic pawns immune to being lit on fire, but heat damage still applies.

Using EMP

Despite their resistance, diaboli are still vulnerable to EMP attacks. However because of the EMPs reduced uptime, you may want to use EMP damage tactically. Stunning the diabolus interrupts the hellsphere cannon, so EMPs can be timed to prevent the cannon from firing and potentially save a pawn's life. If the diabolus is still adapted while firing, and therefore temporarily immune to further EMP stuns, then this strategy cannot be used. EMP should thus be used sparingly, rather than fired at will.

The exception to this is once diaboli spawn with shields, which can be broken instantly by EMP. In that case it is usually better to use EMPs immediately rather than attempt to interrupt a blast. This will kill the diabolus faster, which prevents more hellsphere shots overall.

When you should fight

The first diabolus battle is a major hurdle for any mechanitor. For a solo mechanitor playthrough, a mechanitor armed with an assault rifle, 4-5 militors, and a small crew of labor mechs like agrihands are enough to take out the first diabolus, with the following strategies:

Spread out. Have each militor close enough to the enemies, and labor mechs ready to melee. Ideally, only 1 mech is in the hellsphere blast at a time.
Have your mechanitor & militors focus fire each enemy militor until they die. The faster the small mechs die, the less damage you'll sustain.
Have each labor mech melee a separate enemy. Militors in melee cannot fire their guns, reducing damage accordingly.
With the diabolus inefficiently firing hellspheres / flame bursts at your mechanoids, take it down. The pulse turret can still hurt, especially for the labor mechs, but it should die.

Alternatively, running the diabolus down 30-40 wood spike traps, or 10-15 steel spike traps, is enough to do the trick. A triple rocket launcher can be handy, but don't harm your own mechs!

With a multi-colonist colony, you can have each pawn wield a long-range weapon like the bolt-action rifle or assault rifle. Whenever you get into the hellsphere cannon's range, back off. You can combine this with the aforementioned mech strategies to be more successful. With just the pulse turret to worry about, the diabolus becomes about as strong as 2 pikemen (just with a lot more health).

Analysis - As an ally

Slow and with a little more health & armor than a Centipede, diaboli are best used against stationary threats like sieges, mech clusters, and other mech commanders as well as centipedes. The charge blaster turret is more of a gimmick, when the Diabolus slowly closes distance. It's faster than a Centipede, but not a lot: a speed of 2.4 c/s compared to 1.9 c/s.

But when it's close, it's a tank killer. The Hellsphere cannon is a devastating tool. It does 800 Vaporize damage with an AP of 100%, about 2/3 more than a antigrain warhead. It can easily one-shot or at least massively soften up even the strongest enemy mechanoids. While you can dodge enemy hellsphere cannon shots with some micro management thanks to it's long wind-up time, the enemy won't. They just stand there and get destroyed.

Watch out for the hellsphere cannon accidentally destroying items, including the chips dropped by all 3 mechanoid commanders.

Due to the efficacy of fire against Insectoids, the Diabolus can be an effective way to eliminate infestations, though this risks the Diabolus' own body if the Insectoids manage to destroy it, potentially preventing resurrection and wasting resources, and anything in the room, especially if the floor is made of a flammable material like wood.

Don't use its fire burst in a sufficiently sized killbox against humanoids. That's just cheating.

Health

Specify body type when known.

Body part	Health
Head	113
Skull	113
Brain	45
Nose	45
Neck	113
Jaw	90
Eye ^[1] (left, right)	45
Ear (left, right)	45
Body	180
Kidney^[2] (left, right)	68
Lung^[2] (left, right)	68
Liver^[2]	90
Heart^[2]	68
Spine^[2]	113
Stomach^[2]	90
Limbs (left, right, fore, hind)	135
Appendage (left, right, fore, hind)	90