Optimizing Planar Warfare

[Xihirli]

Against an army of corrupting monsters with a bunch of diverse abilities but that, in general, have the ability to corrupt those they injure to switch sides in the battle, my party has attained a budget of 100,000 gp and the following deal with some devils:

5 sp per lemure/nupperibo
1 gp per imp
10 gp per bearded devil
30 gp per barbed devil
50 gp per black abishai
80 gp per bone devil
120 gp per horned devil
180 gp per narzugon
250 gp per green abishai
400 gp per amnizu
600 gp per pit fiend

Anything not stated costs the same as the next-highest CR of devil above them. I.e., a red abishai costs as much as a pit fiend.

So, hive mind, how shall I build the most optimized, versatile army geared towards minimal casualties (because, as specified, any of our fallen switch sides), keeping in mind that we will be attacking the corrupted on their home turf?

[JeenLeen]

Will the home turf of the enemy have any direct interaction with the devils?
I haven't read the planar rules for 5e like I had for 3.5, but something like if it's a chaotic place it has some detriment to lawful devils.

Is it just injury that leads to them swapping sides, or being killed/KOed (that is reduced to 0 HP)? Assuming the latter, going for higher-HP/AC over higher numbers seems wise.

---

One iffy tactic in direct contradiction to what I just wrote: if your fallen arise as the same creature on the enemy side, having a leading force of very weak lemure/nupperibo to basically absorb hits and clutter the field, while your more powerful creatures use ranged attacks from behind. Yeah, they die and arise as enemies, but they are probably too weak to actually hit your next line of troops much less kill them, so they still act as a buffer against the stronger enemy forces.

But that would only really work for one battle, and assumes a head-on rush to each other, not an ambush or flanking by the enemy (which could occur since their turf). But if you expect one battle, it might be well.

So, like: <line of weaklings expected to die> || <mid-cost devils specializing in ranged attacks> || <reserve force of high-cost devils as a reserve, in case you get flanked>
Probably with a set of flying devils to act as rapid-response and some cheap imps to be able to teleport across your army as messengers.

[Xihirli]

I don't think the home field advantage adds anything like that.

Simple injury can start the transformation, but should give us plenty of time to fix it with a simple 5 hp from a paladin's pool or a Lesser Restoration.

[Pyrophilios]

Get 100 Pit Fiends and 100 Amnizus. Have the Amnizus use their Dominate Monster to convert the strongest opposition to fight for you while the Pit Fiends act as their bodyguards and saturate the area with fireballs to take care of the weaker opponents.

[Envyus]

The Greater Devils seem too cheap. I would just use them.

[tiornys]

Legacy variants or MotM variants? Or can you choose?

edit to add: also, optimal army composition is going to depend heavily on certain resistances/immunities of the enemy, plus their general sensory and mobility abilities. For each of the following, do you know if all/some/none of the enemy might have this trait? And if some, a rough percentage guess would be helpful:

Immunity/resistance to Fire Damage
Immunity/resistance to Lightning Damage
Immunity to Frightened
Immunity to Charmed
Immunity to Poisoned/Poison damage
Immunity/resistance to Cold damage
Flight
Climb speed
Teleportation
Truesight
Blindsight
Devil's Sight


Also, what kinds of status ailments can the enemy inflict?

[8wGremlin]

Remember that a lot of fiends are immune to Fire and Poison.
many have resistance to cold, and non-magical weapons (blunt, pierce, slash, that aren't silvered)

Some creatures can see in the dark, and fly, look at charm abilities to sway some of the opposition to your side.
The Green abishai have mass suggestion, make use of imps with invisibility, and fly.

[Kane0]

So the devils you probably want are

Pit fiends: flight and fear to avoid getting hit, at will fireball spam to blanket the enemy (and allies, since theyre immune to fire). All melee attacks except bite are also 10' reach

Amnizu: flight and ranged stun/blind attacks to avoid getting hit, telepathy for coordination and a 10' reach whip

Narzugon: nightmares fly plus their fear effect to keep enemies at distance, their lances have 10' reach and they can replicate a paladins lay on hands

Green abishai: flight and fear/mass suggestion spells, however neither are at will and has no ranged or reach attacks

Bearded devil: tricky to implement, but their glaives are 10' reach and deal damage over time. If you want to use these you will want to put them on mounts, hide them for strike and fades, cover them with walls of fire, etc.

Edit: also consider Erinyes, who have flight and a solid longbow attack. Nothing fancy, just flying archers.

If you forego bearded devils (understandable) there is no reason to have your army on the ground during combat, assuming its melee attacks that primarily trigger the transformation.

[noob]

Against an army of corrupting monsters with a bunch of diverse abilities but that, in general, have the ability to corrupt those they injure to switch sides in the battle, my party has attained a budget of 100,000 gp and the following deal with some devils:

5 sp per lemure/nupperibo
1 gp per imp
10 gp per bearded devil
30 gp per barbed devil
50 gp per black abishai
80 gp per bone devil
120 gp per horned devil
180 gp per narzugon
250 gp per green abishai
400 gp per amnizu
600 gp per pit fiend

Anything not stated costs the same as the next-highest CR of devil above them. I.e., a red abishai costs as much as a pit fiend.

So, hive mind, how shall I build the most optimized, versatile army geared towards minimal casualties (because, as specified, any of our fallen switch sides), keeping in mind that we will be attacking the corrupted on their home turf?

1gp per imp is such a crazily good deal: if you were fighting non fire immune stuff, 1 scorching ray per gp is just absurd damage.
And the high ranking devils are also really cheap for some reason.

[tiornys]

All Devils from at least Black Abishai up (I don't think it's worth going lower than this) are Immune to Fire and Poison, resistant (or immune) to Cold, and resistant to non-magical weapon damage. Almost all have either Devil's Sight or Truesight to 120'. Fear effects are very common, charm and poison effects a little less common.

Pit Fiends are great if the monsters can't shrug off fire damage because they have at-will Fireball (and again, all of the other Devils are immune to Fire), and excellent if their fear aura also matters. Otherwise they lose a lot of their clout in terms of value per GP spent. They're actually among the weakest in terms of effective HP per GP against AC-targeting damage, and their non-Fireball/Wall of Fire offense is mediocre per GP spent unless the fact that their weapon attacks are magical matters.

Red Abishai have a little lower HP than Pit Fiends but AC 22 vs. 19 makes them more durable against most AC-targeting damage. Their offense is significantly weaker (and among the worst per GP spent) but you almost certainly want about 1 Red Abishai per 5-10 other Devils because they can grant Advantage on all attacks to four allies at a time.

Amnizu are great if the monsters are vulnerable to Charm effects with 3x Dominate Monster per day and Command at will, not to mention Instinctive Charm. If Charm is off the table they're still good although if the monsters have Blindsight and therefore can't be Blinded their ability to debilitate enemies is greatly weakened. They have pretty good damage and decent durability per GP spent and they fly, although they're among the slowest fliers at only 40' movement.

As long as the monsters can't shrug off Lightning damage, Blue Abishai (MotM) are at least great--if the monsters also lack Blindsight/Truesight, can't teleport, and have limited flying ability, Blue Abishai should likely be the backbone of the army. They have the strongest non-Fireball ranged damage output with their 3x per turn Lightning Strikes, plus they have 2x per day Wall of Force to break up enemy formations, and 2x Greater Invisibility to further enhance their offense and defense. On the downside they're among the weakest in terms of effective HP/GP spent so they're not the best choice against flying enemies with Blindsight. And of course if the monsters resist or are immune to Lightning damage they lose almost all of their offensive output.

The next best ranged damage option is the Erinyes, but only if poison damage is effective against the monsters. They're actually pretty durable in terms of EHP/GP and they do decent damage/GP if poison damage is effective. Combine with 60' Flight and these are another candidate for backbone of the army if the enemy is weak on fliers.

If at least a significant portion of the enemy is ground-bound, and especially if they can be damaged by Cold, Ice Devils should make up 5%-10% of the army thanks to Wall of Ice on recharge 6. The wall spam provides for great battlefield control against any enemies within 10' of the ground--but if the enemy is entirely fliers and climbers then other devils are better picks.

Pretty much every devil has considerations like this. Green Abishai can sow a lot of chaos if the enemy can be frightened, charmed, and/or fooled by illusions. Narzugon (assuming they come with Nightmares) are a highly mobile cavalry force with great damage output, but that damage is non-magical weapon and Fire damage and they're one of the few Devils to lack a way to see through magical darkness. Speaking of which, having some Black Abishai around is great if the monsters can't see through enemy darkness since they can spam mobile globes of darkness on a recharge 6 ability--but otherwise they're too weak to bother with. Chain Devils offer the highest damage potential per GP spent (assuming the cost of extra chains is negligible) but are reliant on non-magical weapon damage and are one of the few devils that can't fly. Bone Devils have the highest available EHP/GP ratio as long as they're mostly facing attacks instead of spells, and they also have great damage output if non-magical weapon and poison damage works--but they're among the slowest fliers and are restricted to melee range with almost nothing that works at range. Etc.

[Xihirli]

Legacy variants or MotM variants? Or can you choose?


I believe Legacy variants, the adventure started before MOTM was announced and we haven’t added anything from that book so far.

[Xihirli]

Immunity/resistance to Fire Damage
Immunity/resistance to Lightning Damage
Immunity to Frightened
Immunity to Charmed
Immunity to Poisoned/Poison damage
Immunity/resistance to Cold damage
Flight
Climb speed
Teleportation
Truesight
Blindsight
Devil's Sight


Also, what kinds of status ailments can the enemy inflict?

So the vast majority of the opposing army will, I suspect, be corrupted beasts and humanoids. But the whole thing about them is they increase their numbers by corrupting things, so they could be literally anything. The big ones will I suspect be high CR stuff from all over the place, but probably not aberrations because there haven’t been any of those that I haven’t summoned in the game.

[Xihirli]

All Devils from at least Black Abishai up (I don't think it's worth going lower than this) are Immune to Fire and Poison, resistant (or immune) to Cold, and resistant to non-magical weapon damage. Almost all have either Devil's Sight or Truesight to 120'. Fear effects are very common, charm and poison effects a little less common...

Yes, I think I will be able to gather a bit more information on how they react to Charm and Frighten. Getting a thousand or so Mass Suggestions does seem pretty crazy good, but then, even if they're NOT immune to Charm I can see the whole "the suggestion must sound reasonable" clause screwing us over, since it could be the case that nothing other than "spread the infection to our waiting veins" will sound reasonable.

[tiornys]

I believe Legacy variants, the adventure started before MOTM was announced and we haven’t added anything from that book so far.
Ok, that changes a few evaluations. Most notably it makes Blue Abishai a lot weaker for your purposes.


So the vast majority of the opposing army will, I suspect, be corrupted beasts and humanoids. But the whole thing about them is they increase their numbers by corrupting things, so they could be literally anything. The big ones will I suspect be high CR stuff from all over the place, but probably not aberrations because there haven’t been any of those that I haven’t summoned in the game.
Ok. This is what I'd recommend I think:
40 Pit Fiends (24,000 GP)
30 Red Abishai (18,000 GP)
20 Amnizu (8000 GP)
20 Ice Devils (5000 GP)
80 Narzugon (14,400 GP)
140 Erinyes (25,200 GP)
10 Horned Devils (1200 GP)
40 Bone Devils (3200 GP)
20 Black Abishai (1000 GP)

Pit Fiends, Ice Devils, and Black Abishai (edit: and Amnizu) act mainly as battlefield control. Pit Fiends double as aerial melee if needed. Erinyes and Narzugon are your main damage output; Narzugon double as healers. Red Abishai enhance the attackers and contribute frightful presence effects, and also double as aerial melee. Bone Devils and Horned Devils guard the Erinyes and the casters. Gives you good options against almost anything plus absolute dominance against non-flying enemies.

[Xihirli]

Thanks, I like that army composition!

[Bobthewizard]

I think numbers are your friend here. If you get 10,000 attacks, it doesn't matter if you have disadvantage from long range or darkness. Plus there are so many that AOEs won't make much difference in percentage terms. You also need flight or ranged attacks or you're going to get kited.

I like
25,000 Imps as scouts and to swarm flyers (25,000gp)
2,500 Merregon (CR4 so 30gp each) for archery (75,000gp)

Then you are the commander. No need for pit fiends, or other greater devils.

[tiornys]

Merregon in melee are good value in terms of damage per GP spent, but at ranged they are weak (and they'll have trouble engaging in melee without serious risk of dying and turning). Against AC 18, 6 Merregon at range will deal about half the damage as 1 Erinyes (edit to add: and this continues to hold vs. AC 14)--and they have shorter range, and they don't fly, and their speed is only 30 vs 60, and their weapons are non-magical. They do have better effective HP/GP against attacks targeting AC, but I don't think that compensates for all of the drawbacks.

[Bobthewizard]

Merregon in melee are good value in terms of damage per GP spent, but at ranged they are weak (and they'll have trouble engaging in melee without serious risk of dying and turning). Against AC 18, 6 Merregon at range will deal about half the damage as 1 Erinyes (edit to add: and this continues to hold vs. AC 14)--and they have shorter range, and they don't fly, and their speed is only 30 vs 60, and their weapons are non-magical. They do have better effective HP/GP against attacks targeting AC, but I don't think that compensates for all of the drawbacks.

All good points. I'll trade the Merregon for 400 Erynes. Although I'm starting to think 100k imps might be the best option.

Looking through the options presented, I can't find anything that could stand up to the GP equivalent of imps. A bearded devil might have a chance, but not a good one, then the numbers get even more in favor of the imps. 600 imps definitely wins against a pit fiend.

[tiornys]

Imps do have a lot of merit. Both their effective HP/GP against AC targeting attacks and their damage/GP are an order of magnitude more efficient than the higher tier demons. The only devils that come close in those metrics are the Lemures and Nupperibos, but both of those devils are crippled by their lack of mobility. Imps are listed at Fly 40 and actually have Fly 60 since they can be in Raven form with no change to their other abilities/statistics, which puts them tied for the second best mobility level after Narzugons mounted on Nightmares.

The big downside to Imps is that they have to engage in melee in order to deliver their damage, and they're individually fragile despite the high EHP/GP ratio (which is more about them costing 1 GP than any innate durability). They're extremely vulnerable to (non-Fire/Poison) AoE despite Magic Resistance since their base saves are trash and they're likely to be densely packed. Also, they bring no status ailments or other abilities for battlefield control, and they don't even exert positional control in terms of blocking enemy movement since they are Tiny. These factors mean they are easily killed and corrupted when targeted, and they can't avoid being targeted by even the lowliest enemy troops. If not for the corruption mechanic, having at least 50,000 Imps is likely ideal. However, given that mechanic I think it's better to have troops that can be expected to survive hits long enough for healing to be delivered, that can deliver damage at range or without needing to stay engaged in melee (as Narzugon should be able to do given their mount's 90' fly speed and ability to Disengage and/or Dash while the Narzugon attacks), and that exert battlefield control from a variety of angles beyond straight damage output. Damage type diversity is also nice; the base Imp damage is so high that it continues to be superior even if quartered by Poison immunity and non-magical weapon resistance, but they are vulnerable to being completely shut down by poison + non-magical weapon immunity.

[NecessaryWeevil]

It sounds like the conversion effect lasts a few turns and I'm assuming they stay loyal until it's complete?
In that case, give every melee combatant some sort of explosive suicide device.