This is as of now the most powerful defensive build in the game. We are double jarred into a dybbuk who has possessed a mighty servant of luek-o, which is piloted by 2 chwingas we planar bound.

Mighty Servant?

Mighty servant is the king of defense. Mighty Servant is immune to every condition besides prone and invisibility. Nothing can charm us, frighten us, surprise us, stun us, paralyze us, blind us, petrify us, make us go unconscious, make us take exhaustion, and they sure as hell can’t poison us. This leaves enemies with one way, and only one way, of trying to kill us: damage. [and, possibly, trying to get inside the machine to target our chwingas, but this is an extremally rare scenario we have lots of ways to prevent]

Luckily for us, we are immune to most damage types.
There are exactly 4 damage types that can hurt a mighty servant. Piercing, slashing, force, and thunder. We are resistant to Piercing and slashing, so the damage from those kinds of attacks is rather minimal.

Shield protects us from magic missile, and all spell attacks have disadvantage on us because of our magic resistance, we also have advantage on saves from any spell.

But how does one acquire such a machine? This isn’t DM-fiat. It is currently listed as CR -. True polymorph allows us to form one creature into another ‘of the same CR or lower’, so we need another CR – creature. Where do we find this? prestidigitation. (Yes, Prestidigi-leuk-o tech is real) We can make a 2 headed worm with a null CR and true polymorph it into a mighty servant, which then instantly becomes an inert object. If we need another way to get a CR – creature, tiny servant works as well.

if possession is a magical effect, we just nystul it into a beast and possess it

if possession is not a magical effect, we then nystul it into a humanoid, have a beast possess it, then die inside so it is now the corpse of a beast, then dispel that nystul, turn it into a beast with nystuls, and possess it.

If it is instead considered to be CR0, we can make one out of a familiar or a rock with true polymorph

speaking of true poly, we can use a simulacrum of ourselves to true poly the machine into the corpse of a beast before we possess it before ending true poly, should anyone have an issue with the use of Nystul’s. (thanks Haen)

Even in the event that the mighty servant is downed, it still functions as full cover, giving us ample time to bring it back up. under usual circumstances, lighting damage would allow its regeneration ability to take effect, but our next tech means this isn’t an option. fear not though, as our new option more than makes up for it.

We can also have a druid wildshape into a mighty servant that is nystul’d into a beast. This is incredibly sus and kills the druid, but it’s a small price to pay.

Dybbuk?

This is a very necessary part of the tech. A mighty servant of Leuk-o is immune to any and all effects that change its form once active. It is also immune to planeshifting. This means if we need to go to another plane, even our own demiplane, we can’t. (unless the demiplane door isn’t ‘an effect’ but this is a weird gray area).

Very important note: we’re using the old version of Dybbuk here

this does sadly mean we can’t benefit from the servants regeneration, we can however re-possess the servant to regain 310 temps. This does require it to be nystul’d into a humanoid or beast. This is fine since it’s immune to all spells and effects that target those types, however re-possession could become difficult in the case this is dispelled. It also has to be of large size. Thankfully, an inert servant is only large size, as it is specified as being 10ft. I’d go with beast typing, because this makes us immune to other forms of possession.

Be sure you have pilots in place first, we don’t want to be inhabiting an inert object.

Also, just because our usual form is immune to all effects doesn’t mean we ignore them at all times, keep mind blank up at all times and continue to smoke black sap, this way if we’re put into dybbuk form we can’t be charmed or feebleminded.

We can end our possession as a bonus action, and possess as an action on a recharge. We can very well keep a corpse inside the mecha, in the event we need a new corpse and can’t evac our chwingas. Corpses worth considering are a half-dragon drow favored consort and/or a marilith on our backs

If we are forced out by the depletion of our temps, we go into dybbuk form, we can use our incorporeal movement to get back inside the mech without anything else being able to.

To increase our defense further, we can add death ward stacks and chwinga charms to ourselves. With charm of 9 lives, it’s very unlikely anything would have time to down us before we can simply re-possess the servant or a back-up corpse, and the fight continues. [we get death ward from simply being a witherbloom student]

Dybbuk can also help us with a limiter on the mighty servant: our lack of fly speed. Dybbuk has at-will dimension door, which our pilots can use. We can combine this with feather fall. to gain a pseudo-fly. We may lose a pilot doing this, as dimension door allows us to bring objects ‘and one willing creature’. The rocks chwingas inhabit could count as our objects, or they might not. Chwingas also can’t be targeted by spells while in their natural shelter, so if this ruling is in effect one must use their action to emerge while inside the servant.

Given this, though, it seems likely we can treat the rocks as objects, and dimdoor with both.

Another solution could just be to use the ‘fly’ spell, or immovable object tech. Immovable object tech is actually amazing on a mighty servant as we have extra jump height and length. We also have the option of casting ‘tashas otherwordly guise’ for a 40ft fly speed that we get 3 times a round and another attack. I’d keep this around as a prep, fly speed is important even if it’s expensive. The extra attack is nice too. attacking isn’t a bad option when you have +17 to-hit and each one is 36 damage. (tripled for objects, if that matters)

We can also uses draconic transformation for a 60ft flyspeed, making it rather hard to try and kite us in a fight.

Chwinga Pilots?

Yes.

This gives us more actions, as the chwingas can take actions for the mighty servant.

“As an action, you can command the servant to take one of the actions in its stat block or some other action.”

This means we can either use them to make attacks, or even to cast spells.

Why chwingas specifically? They can cast guidance and pass without trace for one, which means we can essentially have both always active. And, chwingas can inhabit stones, giving them full cover. This means even if something, somehow, were to inflitrate our mighty servant, all they’d have access to is some rocks which they likely don’t know contain chwingas. We can go through steps to hide these, I recommend putting them in a container and to put that under an arcane lock, then repeat this process a couple more times. I would also physically secure the boxes somehow. chains, ropes, ect. Set all of them to open on our command word so we can easily evac the chwingas should we need to (and we may need to). Because they are still ‘inside the machine’, they can pilot it even through several layers of full cover.

Why not another elemental? Well, simply put, those won’t give us as much in terms of defense.

Special care should be taken to avoid *ghost in the machine*

Ghost in the Machine. Upon his death, the soul of the mighty warlord Leuk-o was drawn into the artifact and has become its animating force. The servant has been known to attack or move of its own accord, particularly if doing so will cause destruction. Once every 24 hours, the servant, at the DM’s discretion, takes one action while uncrewed.

If the servant loses half of its hit points or more, each creature attuned to it must succeed on a DC 20 Wisdom saving throw or be charmed for 24 hours. While charmed in this way, the creature goes on a destructive spree, seeking to destroy structures and attack any unattuned creatures within sight of the servant, starting with those threatening the artifact — preferably using the servant, if possible.

This will likely never come up and even it does, it’s more than manageable, likely they’ll begin punching our enemies. but we don’t want our chwingas to be charmed by the machine itself either way. We can avoid this by making them smoke black sap. Black sap can be bought on the market or made through the creation spell if we are not a conjurer. We can’t allow this, as we are the ghost in the machine, not Leuk-o. His soul is completely and utterly subjugated to ours. We are the master of Leuk-o.

We can also keep a supply of chwingas handy in more rocks encase we need a spare pilot to attune to the machine, this however takes a day.

The pilots can also maintain full control even if we stop possessing the servant, say from taking enough damage and being ejected, this means we are now forced into dybbuk form, but the mech functions as normal, with pilots under our direct control.

Using incorporeal movement we can also simply hide back inside the mech and use its full cover while we either possess it, one of our back-up corpses [I recommend a drow favored consort], or simply peek in and out casting spells.

Now comes the real shit

“As an action, you can command the servant to take one of the actions in its stat block or some other action.”

Assuming the chwingas are controling us and ‘some other action’ includes ‘our actions’ and/or that we have a statblock as a player character, we run into the idea that chwingas can cast spells from our list. Under a particular reading, chwingas can cast from our list, using our slots, but on themselves and using their own concentration, akin to casting from a magic item. this opens up entire worlds of tech. including the dreaded triple concentration, where we can cast 3 different concentration spells, 2 of which we can do on the same turn.

Awaken?

if we can cast awaken on our machine, we can have it act on its own turns as well as the chwingas if we were to get out of our machine, however the line “The DM gives statistics to the plant” means we want to do this as a beast only.

The mighty servant may try to attack us after 30 days are up if we don’t nystul it into something else and planar bind it, but, we could also make it more potent in phase 2. This is a weird trade off. “The target also gains the ability to speak one language you know.” is also somewhat useful, as it means our mech can communicate with us while we’re not possessing it.

AC Stacking

22 AC not enough? Lets boost it some more!

Always on:
A mundane shield: +2
ceremony: marry your chwingas and refresh it by marrying another creature and killing it every 6 days: +2 AC (or marry another elemental that just chills in the mech, depending on interpretations on the natural shelter)

Spell options:
Tashas otherwordly guise: +2 AC
Shield of faith: +2 AC
Haste (don’t bother): +2

Subclass specific:
Bladesong: +5
beast barb: +∞

Resting AC: 26
Plus shield: 31
Plus Spells: 37 (using multiple conc spells)
Plus Bladesong: 42

31 AC means a tarrasque needs 7 rounds of only attacking us to get rid of our temp health, at which we re-possess the machine and it would need another 7 rounds of uninterupted attacks to take us out, at which point we likely have our possess ability back.

Even more defense

We can keep PWT up at all times as well as guidance or resistance. We have shield and silvery barbs, as well as absorb elements for thunder damage. to negate a big source of force damage a that is magic missile and we can force re-rolls on crits. We take lucky to force more re-rolls and secure super high initiative. We can use fortunes favor to add even more re-rolls.

we can use infinite-jar tech to have our dybbuk form have near limitless health. this is somehow even more questionable than the rest of this guide.

Contingency: resilient sphere is good for dybbuk form, we can be unable to be targeted for as long as we need to recharge our possession again. We start fights with one, and likely just get it back in the time it takes to down our temps, so this all but guarantees we’ll get 2 uses of possession a fight at minimum.

If we are a conjuration wizard [Which is what I reccomend this, as it maximizes defense in this scenario], we can also use ice troll hearts for our dybbuk form, if we are somehow downed, and our regen doesn’t work, we use elixier of life to have advantage on death saves. We of course also have clones set in place in various demiplanes, some of which we know about some of which we don’t. our buff glyphs also are free now, thanks to tax evasion.

I recommend conjurer both because of my own biases and because someone with this much defense should be capable of healing the team somehow, ice troll heart and white ghost orchid lets us keep the team up and bring them back. We can take the witherbloom background in order to get revivify as well. Conjurer still increases our defense greatly, even at this high a level. Catapult munitions while we have a sanctuary up will also give us a high offense capacity while being even harder to hit with attacks.

If we’re a chronurge, we can force ourselves to pass saves using our reaction. We also still have clones.

An abjurer wizard can use their ward for a bit more sturdyness here, but it’s not anywhere near as good a defense as the others defense. A bladesinger can use their bladesong in this form for extra AC, again, not particularly useful. Song of Defense has marginal use at least, since at this level it’s not a death sentence to use a 5th level slot like toilet paper. The obvious choice is still either conjurer or chronurge.

We could also use glyphs to buff ourselves if we have extra prep time, take a look here for a guide to glyphs, don’t use tenser’s transformation glyphs as we both would lose most of our temp HP and our ability to cast spells. One I don’t mention in the guide that’s useful is fizbans platinum shield, which gives us evasion and half cover.

We can cast fog cloud, or use prestidigitation for obscurement, and with our blindsight make all attacks at advantage. We also can’t be targeted by spells that require sight while doing this. A glyph of greater invisibility would also add to our defenses, as would tashas guise as a means for 60ft flight. Remember our chwingas can also make us move on their turns with no action cost. So a 30ft fly from the fly spell is a 90ft fly speed in total, and a 60ft fly from tashas is really 180. This is very close to phantom steed levels, and we can still dash to go even further.

Sanctuary would also greatly increase our defense, forcing creatures to make a wis save to attack us and then meet our rather high AC. Using marriage tech and a mundane shield grants us 26, and up to 31 using the shield spell. This gets higher with glyphs. With sanctuary up we can refuse to attack ourselves and make our pilots do it, or even conjure catapult munitions.

We also function as an actual tank for a party, as a party member can be placed inside the mighty servant and gain full cover. They can dimdoor in, or use movement when the hatch is open to climb inside. A conjuration wizard can also revive dead allies once fights are over and keeps them well healed.

We can cast rope-trick inside the mighty servant to place our chwingas inside of to make it go inert so we can re-possess it. Since the mighty servant is nigh impossible to destroy, we can use this trick to short rest mid combat. heck, if they don’t have a way to get inside (knock, lockpicking) or access to the machine of lum the mad, we could long rest inside of it.

if our dybbuk form takes damage, it heals both from the mighty servants regeneration and our own once we re-possess it. this is 25 hp a turn.

Spells we should take to cast in a fight:
Fog cloud (assuming no prestidigifog)
Dispel magic
Counterspell
Tashas otherwordly guise
Disinitigrate (easier time getting out of force cage, WoF, with our pilots in tow)
Shield, Silvery Barbs, Absorb Elements
Invulnerability [10 minutes of uninterruptable morbing]

conjure minor elementals:
give us charms, our dybuk form and the servant on its own can now both have the charm of 9 lives, which functions as 9 stacks of death ward that can’t be dispelled.

Charm of the crystal heart also gives us immunity to non-magical piercing and slashing. it gives us vulnerability to bludgeoning but we are immune to it.

Charm of travelers haven is a tiny hut as an action, useful for our teammates or our chwingas but not as much for us

“Dark Gift of Tarakamedes, the Grave Wyrm” gives us a fly speed of 50ft but forces us to eat a pound of bones a day or die. This sounds bad, but we can use death ward to negate it, and dying doesn’t negate the fly speed, so we may have a way to have permanant flight if we use charms.

Feat: Metamagic adept
We take this so we can use a subtle counterspell to negate a high damage spell or dimdoor to fully get out of a fight.

A note on Antimagic Field

Antimagic field, on the face of it, may seem to be our doom. Our spells don’t work, and magic items and summons disappear in them. However, take a closer look at the spell “anti-magic field”

specifically, this section: “Spells and other magical effects, except those created by an artifact or a deity, are suppressed in the sphere and can’t protrude into it. “

So, once we become the ghost in the machine, we also become an artifact, which also means we are immune to the effects of anti-magic field. Our spells are also immune to the effects of anti-magic field. it’s possible it still shuts off the artifacts abilities, but not our abilities.

“Magic Items. The properties and powers of magic items are suppressed in the sphere. For example, a +1 longsword in the sphere functions as a nonmagical longsword.” This section comes after the “spells and other effects made by artifacts are immune”, so, it’s very likely that it applies, but still a wording debate. So we do the entire loop back to ghost in the machine while being the ghost in the machine, so all of our stuff is magical effects made by an artifact, which is immune to AMF. that, or, since we are an artifact, this rule applies already. from this point, even if we were to be caught in an antimagic field, we could simply move out of it or even use spells while inside it, so long as we don’t revert to dybbuk form.

Counterspell?

since our chwingas can cast spells and can do so from full cover, there is nothing that can counterspell us on those turns.

Chwinga Defense

We have access to chwingas, so chwinga charms are a way to get 9 lives on our chwingas to make them very hard to kill. We can also get death ward and cast it multiple times.

We want to cast nondetection, and make sure no one knows anything about our chwingas including info that would allow high level casters to cast gate on them.

We can fill the entire machine with concrete or ball bearings, then cast immovable object, making it impossible for anyone to get inside. I’d personally keep a spare corpse in it then fill it with stuff. like ball bearings.

Speaking of immovable object, use immovable object on a string on the hatch into the machine so it’s even harder to open, as well as using it on the boxes the chwingas are in.

nystul our chwingas into another type, further increasing how hard it would be to know what is inside of our mecha

use private sanctum over your base to prevent any peepers, keep a room free of private sanctum so you can still cast divination spells yourself, but otherwise don’t interact with the room.

We can also add more chwingas in rocks that aren’t attuned, so even if enemies do get the drop or can get into our mecha, they’d have to play a guessing game at which rocks to break.

Nystul them into something that can’t be planar bound so enemies can’t wish-bind them, then nystul them back when you need to re-apply planar bound once every few months.

We can also apply aid at 8th level to add some hp, using wish glyphs or otherwise.

resilent sphere would still allow them at the controls and prevent all spells from coming through. If we see ahead of time we’re going to be dealing with chain lighting through objects, we can use resilient sphere before the fight. Glyphs of resilient sphere and moving them into the machine using an unseen servant is doable, but only lasts 1 minute. Because the chwingas can take actions from us, we can contingency cast resilient sphere on them to be triggered upon a command word.

We could also true polymorph creatures into chwingas, and if they’re destroyed they become, say, invisible stalkers, which are still attuned to the mighty servant of leuk-o. (We can maybe stack potentially infinite true polymorphs for infinite health, but infinites aren’t what we do here)

Tiny Servant Matryoshka

we can cast tiny servant on the rocks our chwingas are inhabiting and apply aid/death ward to increase their defense even more. These tiny servants could also be given Font water (from the conj guide) to have access to greater restoration or other spells, if they attune to the machine and then un-attune to let the chwingas re-attune.

Offense Potential

While this is primarily a defensive build, our offense is also very, very good. with just punching once on our turns, we can do 122.6 dpr. This already beats some of the better damage builds in the game.

if we have a source of multi-attack, such as tashas otherwordly guise or being a bladesinger, we can use each turn to attack twice, as the machine can take the attack action. This doubles our attacks from 3 to 6 and quite obviously also doubles our dpr to 245.2 (assuming 19 AC).

without extra attack or in the case of bladesinger, we can look at booming blade. Assuming we can cast booming blade, which is questionable, because the fists of the mech have no inherent value, silvering them might be an option if they’re considered weapons, but this may still not make them have an inherent value.

Alternatively, we can use the pre-tashas version of booming blade from SCAG, which is still an official sourcebook.

“As an action, you can command the servant to take one of the actions in its stat block or some other action.”

We can also cast spells on all turns, as mentioned in the pilots section. With that trick, we could very easily put down 48 flying snakes using 2 5th level and a 6th level slot. We could also use these for owls to do divebomb tech.

Ultimately, offense on this build is amazing even without investing more spells into it once it is going.

Control Potential

Ever need a microwave but can’t concentrate on sickening radiance as well as wall of force? well, now you can. as well as adding in another conc spell.

Ultimately, this build lets you combo with yourself, be your own buff caster and not waste turns, and you can survive inside your own microwave to really hammer down on that one lone enemy before moving to the next one

What kills us then?

Well, it takes roughly 6 meteor swarms of thunder type to force us out once of the servant, assuming we don’t use absorb elements. We can go 7 rounds with a tarrasque in melee, if the tarrasque is being smart, before going into dybbuk form. We can also just default kill it. Greatwyrms with force breath stand some chance of killing us. If they get their breath weapon every round and we fail every save, we take 5 rounds to force out of mighty servant form. This leaves us plenty of room to re-possess the servant. Keep in mind, the servant can continue to function without us thanks to our pilots, and it gets even harder to take down. if the servant itself goes down, we can apply lightning damage to it to bring it back up, or simply feed it an ice troll heart and it gets back up on its turn anyway (if it can be said to have turns). We have a very real possibility of being able to take on multiple gem greatwyrms ourself using this tech.

this is all ignoring infinite jar tech and our stacked death wards on our dybbuk selves.

We also can just leave fights with teleport or dimdoor, just to come back later.

A hexvoker with max int and cha that also gets around our shield would take exactly 2 rounds to go through our temps using their 8th and 9th level slots. In that time we can feeblemind them, force cage them, dark star them, or worse. We also can re-possess ourselves at which point it’s going to take them 3 turns to force us into dybbuk form again. all this while our pilots take shots at them with destructive fist. once forced out the first time we could just allow our mech to punch them out while we put down obscurement so they can’t cast magic missile unless they’ve got blindsight.

If we strike the machine of lum the mad we do instantly die, so i recommend we destroy this artifact as soon as possible. We can do this with another mighty servant and using our simulacrum to do the dirty work, then simply make another sim of ourselves as a dybbuk to possess another mighty servant with 2 more chwingas.

We can have a simulacrum by our side and be 2 ghosts in the machine together.

We could also potentially make a planar bound army and put them all in mighty servants for an unkillable mecha-army, but nigh-infinite armies are God-exit so we don’t do that.

Epilogue

It takes even the best possible damage counters to us multiple rounds of constant aggression to even phase us, which we can often undo in an action. We get 3 turns per round, thanks to pilots being able to take actions ‘of the mech’ which is us. We make glyph planetar martials look like a joke as they attempt to hurt us. We bare-knuckle box Tarrasques because it’s funny. hexvoker poops their pants at our sight. a gem greatwyrm in their right mind would flee from us instantly, knowing we are impossible to take down. in all likelyhood, it takes a combination of control and massive damage to even begin to think to take us down. a truly crushing series of moves to both body and mind, as we really are the ultimate ghost in the machine.