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

One or more diaboli can spawn in mechanoid raids when sufficient raid points are available for them, however they are also involved in the mechanitor progression and can be specifically summoned by the player.

Summoning a diabolus requires a mechanitor and a powered comms console. Constructing a comms console requires the Microelectronics research. Unlike the buildings used to summon the other mechanoid commanders, the console is not consumed in the process.

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 6. 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.

Every diabolus will drop a separate signal chip, it doesn't need to be "the boss" of a wave, or even to come as a summon.

Acquisition

Diaboli can be gestated by a mechanitor at a large mech gestator once the high mechtech research project has been completed. Note that this research requires a powerfocus chip to unlock. Each requires 300 Steel, 300 Plasteel, 2 Signal chips, 1 High subcore and 12 gestation cycles taking 1,800 ticks (30 secs) each to initiate.

Dead, friendly diaboli 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.

Dead diaboli may be shredded at the machining table or crafting spot for 50 steel and 20 plasteel. However, these values are affected by mechanoid shredding efficiency, as well as missing parts on the diabolus.

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 5 wastepacks to go from empty to full charge. This totals in 25 wastepacks whenever the recharger's waste is filled up.

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. This circle indicates where Diabolus is aiming. It is to be noted that unlike almost every other weapon, the Hellsphere cannon will not track its target while aiming and will instead keep aiming at the same spot. After a 450 ticks (7.5 secs) warmup, the cannon fires an extremely fast explosive projectile, which upon exploding will leave 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.
- The explosive projectile 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. However, due to the fact that Vaporise damage does not overflow, the majority of this damage often ends up overkilling just one or 2 body parts, leading to much lower effective damage output
- 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" on a 2,700 ticks (1.08 in-game hours) cooldown. It begins emitting visible fumes and randomly depositing chemfuel puddles in spaces within 5.9 tiles around itself; after 3 seconds, it fills in the remaining spaces in that radius with chemfuel puddles and releases a 10-damage Flame explosion with the same radius, dealing damage and igniting the puddles. As of 1.5, enemy diaboli that are currently 'fighting enemies' (as opposed to wandering around in preparation for an assault, pathing towards a colony, or opening fire on random buildings) will use their fire burst if attacked or even just aimed at by a pawn within 65 tiles, regardless of whether or not the burst would hit anything. Player-controlled diaboli must have their fire burst manually triggered by the player.

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.

Psycasts

Diabolus, with its 0.75 sensitivity, is vulnerable to certain Psycasts. Beckon will interrupt either of its charged attacks, even if immediately broken by damage. Berserk on its ally can cause it to waste a lot of time on charging a friendly fire attack, which it cannot interrupt on its own. Berserk cannot be cast on Diabolus, since like other mechanoid commanders it's immune to psychic insanity.

Diabolus is too big to be affected by Skip psycast and its variants.

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).

As a counter raid

Diabolus (and any mech boss) can be summoned defensively against any other non-mech raid, sometimes to a great efficiency since hostile raids will more often than not prefer to fight each other and Diabolus can be summoned every 2 days without any additional buildings which can make certain endgame sequences considerably easier.

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.

Diabolus can destroy obelisks in one hit, removing them from map without triggering their activation effect.

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.

When using the remote shielder, be very careful. If the shield is active when the hellsphere cannon is fired, the shot will hit the shield, damaging the Diabolus and anything within point blank range.

Health

Body parts

Part Name	Health	Quantity	Coverage^[1]	Target Chance^[2]	Subpart of	Capacity^[3]	Effect if Destroyed/Removed
First body ring	247.5	1	100%	10%	N/A^[4]	Moving Manipulation	Death −16.6% Moving −16.6% Manipulation Will never take permanent injury
Head	135	1	10%	3.4%	First body ring	-	Death Will never take permanent injury.
Artificial brain	45	1	10%	1%	Head	Data Processing	Death Will never take permanent injury.
Sight sensor	45	2	8%	1.3%	Head	Sight	−25% Sight. −100% if both lost. Will never take permanent injury.
Hearing sensor	45	2	8%	1%	Head	Hearing	−25% Hearing. −100% if both lost. Will never take permanent injury.
Chemical analyzer	45	1	8%	1%	Head	-	Will never take permanent injury.
Bulb turret	180	1	5%	5%	First body ring	-	Will never take permanent injury.
Second body ring	247.5	1	75%	3.7%	First body ring	Moving Manipulation	Death −16.6% Moving −16.6% Manipulation Will never take permanent injury
Reactor	90	1	5%	3.8%	Second body ring	Power Generation	Death. Will never take permanent injury.
Hypercapacitor	225	2	10%	7.5%	Second body ring	-	Will never take permanent injury.
Third body ring	225	1	70%	16%	Second body ring	Moving Manipulation	Death −16.6% Moving −16.6% Manipulation Will never take permanent injury
Fourth body ring	202.5	1	70%	15%	Third body ring	Moving Manipulation	Death −16.6% Moving −16.6% Manipulation Will never take permanent injury
Fifth body ring	180	1	60%	11%	Fourth body ring	Moving Manipulation	Death −16.6% Moving −16.6% Manipulation Will never take permanent injury
Sixth body ring	157.5	1	50%	10%	Fifth body ring	Moving Manipulation	Death −16.6% Moving −16.6% Manipulation Will never take permanent injury
Fluid reprocessor	67.5	1	5%	0.55%	Sixth body ring	Fluid Reprocessing	Death Will never take permanent injury

↑ Coverage determines the chance to hit this body part. It refers to the percentage of the super-part that this part covers, before its own sub-parts claim their own percentage. For example, if the base coverage of the super-part is 100%, and the coverage of the part is 20%, 20% of hits would hit the part, and 80% the super-part. If the part had its own sub-part with 50% coverage, the chances would be 10% sub-part, 10% part, 80% super part.
↑ Target Chance is the actual chance for each part to be be selected as the target when each part's coverage has been taken into account(I.E. Neck covers 7.5% of Torso but Head covers 80% of Neck so it actually has only a 1.5% chance to be selected). This is not pure hit chance, as different damage types propagate damage in different ways. See that page for details.
↑ Note that capacities can affect other capacities in turn. Only the primary effect is listed. See specific pages for details.
↑ This is the part that everything else connects to to be considered 'connected'.

Gallery

Age 0-99 Diabolus facing east
Age 0-99 Diabolus facing north
Age 0-99 Diabolus facing south

Age 100+ Diabolus facing east
Age 100+ Diabolus facing north
Age 100+ Diabolus facing south

Version history

Biotech DLC Release - Added.
1.4.3527 - Fix: match diabolus fire burst range to its range overlay.
1.4.3528 - Fix: Diabolus has two 'first' body rings.
1.4.3530 - Fix: Comms console diabolus threat cannot be called by mechanitors if mech faction is disabled.
1.4.3531 - Increased EMP resistance from 30% to 60%. Added alert for incoming bossgroup. Fix: Bossgroup mechs do not attack if mechanoid faction is disabled.
1.4.3534 - Fix: Diabolus' fire burst shoots fuel through the walls.
1.4.3541 - Fix: When the mechanoid faction is disabled, mech bosses will not attack pawns.
1.4.3555 - Now immune to psychic lances. Super-mechanoids cannot be called when there is already another super-mechanoid on the way.

Mechanoids

Mechanoids | Core: Centipede (Blaster, Burner, Gunner) • Lancer • Pikeman • Scyther • Termite
Combat: Centurion • Legionary • Militor • Scorcher • Tesseron
Command: Apocriton • Diabolus • War queen (War urchin )
Labor: Agrihand • Cleansweeper • Constructoid • Fabricor • Lifter • Paramedic • Tunneler
Cluster | Buildings: Condition causer • Count-down activator • Mech assembler • Mech capsule • Mech drop beacon • Mech high-shield • Mech low-shield • Mech node • Proximity activator • Unstable power cell
Turrets: Auto charge turret • Auto inferno turret • Auto mortar • Mini-slugger turret
Creation | Pawn: Mechanitor
Buildings: Mech gestator • Large mech gestator • Mechband antenna • Mechband dish

References

^1 - Cynapse - Ludeon Developer, Rimword Official Development Discord 22 Jan 2023

[1] Coverage determines the chance to hit this body part. It refers to the percentage of the super-part that this part covers, before its own sub-parts claim their own percentage. For example, if the base coverage of the super-part is 100%, and the coverage of the part is 20%, 20% of hits would hit the part, and 80% the super-part. If the part had its own sub-part with 50% coverage, the chances would be 10% sub-part, 10% part, 80% super part.

[2] Target Chance is the actual chance for each part to be be selected as the target when each part's coverage has been taken into account(I.E. Neck covers 7.5% of Torso but Head covers 80% of Neck so it actually has only a 1.5% chance to be selected). This is not pure hit chance, as different damage types propagate damage in different ways. See that page for details.

[3] Note that capacities can affect other capacities in turn. Only the primary effect is listed. See specific pages for details.

[4] This is the part that everything else connects to to be considered 'connected'.

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