[3.19] Inquisitor Armageddon brand + Firestorm with MoM and EB

The goal of this build was to make a build that can be started on any budget and gear but can also quickly grow to do comfortably and quickly start at T16 maps with a budget of no more then 100 to 200c and naturally grow in to gear do all endgame content and pinnacle bosses from there.
The second goal was to be something like a fire mage that used big balls of fire and what better ball of fire then a meteor. Both Armageddon brand and Firestorm fit the description on those visuals and as I noticed they also scale off on the same stuff really well. Final goal was to have enough freedom left in gearing and talents to tune it more towards defenses or offenses depending on the wish.

Pro's
- Visually pleasing
- Very linear and rewarding progression. You just keep on improving
- Good clear speed for maps
- Decent boss damage
- One of the cheaper builds to push to t16 maps,

Con's
- You can reach t16 maps quickly and on a budget but the final push to increase your gear so that you can comfortably farm guardians and juiced t16 maps gets expensive.
- While though enough to comfortably farm high end contend you do sometimes still die so probably not suited for Hardcore.
- While you can solo farm the devouring diadem easily and so you could play it in ssf, getting a good watchers eye and good corrupted flesh+flame jewels will be hard and those do provide a lot to the build even though they are not mandatory. I have not investigated alternatives to this.
- You wont be killing Sirus in under 10sec but you could within a minute.

For defenses the build makes use of a couple of mechanics.
Mind over Matter
The first is Mind over Matter. With MoM it splits 40% of the damage you would take on life off to your mana instead. If your mana reaches 0 then that damage is taken from your life again and so your mana pool basically counts as your life pool as well. To begin with 40% will enough but our goal is to reach 50% of damage taken from mana before life so that incoming damage is split evenly between life and mana.

Eldritch Battery
This build spices things up a bit by adding Eldritch battery to the mix.
Normally you would stack mana when you use MoM but because we use Eldritch battery there is no need to do so. EB causes your energy shield to protect mana instead so in combination with MoM we will be splitting damage between life and energy shield. Doing this will also cause all your skills to use energy shield instead of mana and so we won't have to consider mana costs at all.
While doing this does not directly increase our effective HP it does have a huge benefit of doing so that will hopefully become clear after I explain the other defensive layers.

Inquisitor ascendancy's "Sanctuary" and "Pious path"
Sanctuary will cause effects of consecrated ground to linger and with this we can keep up consecrated ground at any time. It also provides a nice damage boost against enemy's.
Pious path adds to this by causing our very high life regeneration to also apply to energy shield and is one of the main reasons the MoM+EB combination works well for this build.
This build has no trouble reaching up to 1.5k or 2k life regeneration per second which can apply both to life and energy shield simultaneously. This means that if both life and energy shield would be damaged we could get up to 3k to 4k regeneration per second in total if we'd split incoming damage evenly between life and energy shield.

Petrified blood
Petrified blood prevents 40% of life loss while at low life and deals 80% of that damage to you over 4 seconds instead. As it's life loss and not damage taken it also counts for other effects outside of straight up damage but it does not apply to the portion of damage that is applied to our energy shield.

Effectively it means that you will only get 60% of a hits damage on your life pool directly, 32% will be converted in to a 4 second damage over time, and 8% will completely be negated.
In order for this effect to work we need to be at low life at all times. The best way to achieve this is to reserve 50% of our life.

Note:
One thing I am not sure on yet at this point is as to which mechanic is applied first. Does MoM first split a incoming hit over our life and energy shield and does PB then further reduce the hit by 40% on our life or does BP first decrease all incoming damage by 40% and then split the remainder over our life and es pools.
The first would mean that our PB decreases a smaller portion of the total damage so we take some more overall damage and as a result the life loss over 4 seconds part is a bit lower as well.
I hope its the second option and that PB is first applied

Ailment immunity
You will want immunity to stuns, freezes, and shock at the very least.
My preferred way of doing so is using Purity of elements for all ailment immunity's and to use a darkness enthroned stygian belt together with 2 abyssal jewels that grant at least 28% chance to avoid being stunned. The jewels can also roll a second modifier like to avoid bleeds, hinder, etc which can be nice.

Curse mitigation
With the recent change to consecrated path it now gives 75% reduced effect of curses on you while affected by consecrated path. Due to our talent we will always have that effect and with a tiny investment of 3 talent points on to the Asylum node we will reach 100% reduced effect of curses on you.
This is not "immunity" so you will still be cursed but the curse wont have effect. This enables the use of "while cursed" mechanics but this build does not use those at this moment

Enduring cry
Enduring cry has an interesting interaction with this build.
EC benefits from our Templar ascendancy's which means it also restores energy shield. In addition it scales with increases to life regeneration as well so while the tooltip might say something in the lines of "restores 2k life over 1 second" in reality it comes closer to 3k life AND energy shield which is insanely strong when in a pinch

We are using 2 spells to dish out the damage.

Elemental overload
As this build leans on a quite heavy investment in to brands and defenses there isn't a lot of room left to do meaningful investments in crit. We also don't have room for investment in ignite either. We do however reach somewhere around 10% crit chance for our spells and that means that we do crit enough to trigger Elemental overload and keep it up 100% of the time. This provides us a flat 40% more damage boost.

Pain Attunement
As we are running a low life build in order to get petrified blood to work properly we might as well take full advantage of our low life status and run with Pain attunement as well. It gives us 30% more damage while at low life. Great right?

Armageddon brand
The first and our main meteor slamming skill of choice is Armageddon brand.
The skill activates once every 1.5seconds by default and hits all enemies in range for a nice chunk of damage when it does.

The gem setup for this one is straight forward, whatever deals most damage.
The only thing to take in to consideration is that you want to be at around 10% crit chance so that it's easy to permanently keep Elemental overload up so don't use (awakened) controlled destruction if your crit would fall below like 7%. Not having EO up is a massive damage loss, More then controlled destruction would give you compared to any other gem.

The other thing is that I personally prefer my aoe radius to at least be 26 or higher for this skill. While it isn't needed I do feel like map clearing becomes slower and more sluggish if it drops to low and so I prefer not to use concentrated effect unless I have some good sources for aoe

The final one is that you can't trigger arcane surge in a normal way on this build as you're spending energy shield instead of mana and that does not count for arcane surge. There are other ways to get it and my favorite choice here is to get a watchers eye that grants it on hit while you have zealotry

Firestorm
This is our backup skill and here we can choose between using it as a means of extra damage on the tougher mobs or bosses or to use it as a utility skill.
Either way you really want to at least use combustion and avoid elemental focus here so that you can apply the -10% fire resistance buff to ignited enemies. Did you choose damage then any gem will do, even concentrated effect as you will be using Firestorm mostly against individual though mobs anyway.
In terms of utility I like to socket onslaught and culling strike in there. Early game I also use hextouch + flammability as long as I don't have a item that applies the curse on hit.

Helmet: The Devouring Diadem
This helmet is the only mandatory item in the build. It requires level 54 and can be obtained by killing Catarina the final boss of the Immortal Syndicate.
As it's among the highest drop rates together with the flask you normally only need 2 or 3 tries if you are not particularly lucky so it is perfectly possible to get it in SSF as well. For trade league it's always only been a couple of chaos so it's perfectly obtainable for everyone.

The helmet does 2 things for us
It gives us Eldritch Battery which is mandatory for the build once you start pushing the end game bosses. The second is that it gives a 25% increased reservation efficiency for socketed gems. It also gives some stats and energy shield which is nice.

To fully utilize this helmet we link 2 red gems so that we can run arrogance with any of the 35% reservation aura's we use. This will cause it to reserve life instead with the benefit of reduced reservation costs and bump our health down to around 52% unreserved. The other 2 sockets should not be linked to to the arrogance gem and to run at least 1 50% aura.
The second slot depends on if you can and want to get additional reservation efficiency. If not then a 35% aura like herald of ash or summon skitterbots are your options. If you can get more reservation efficiency trough corrupts on jewels, corrupt on helmet, or the sanctuary of thought ascendancy trough the forbidden flesh/flame jewels then you could run a second 50% aura

Ring: Polaric devastation
The polaric Devastation is a unique ring that when fitted in the left ring slot will cover enemies on ash when you ignite them. This causes enemies to take 20% increased fire damage and have 20% less movement speed and is the reason why we want one of our spells, in this case Firestorm to apply ignites. You wont be using this effect while clearing normal mobs but once you find a tougher mob like a boss then you can apply this for a nice extra boost.
The ring is in no way mandatory but as far as I could see it was one of the best AND cheapest ways to get a significant damage boost.

Weapons
For this build I prefer dual wielding wands as this is overall both the cheapest and the best option for dps.
You could however choose to go for a 6link staff so that you can socket utility gems on to your firestorm links but that would mean giving up other sockets which so far I didn't like to do.

Regardless of the weapon(s) you choose the stats you are looking for on your weapon will be the same.
In order of importance:
Prefixes
1 - Increased levels of (all/socketed) spell skill gems, the more the better
2 - Increased spell damage,
3 - Adds # to # fire damage (here either to attacks or to spells works as we are using battlemage. Pro-tip, the regular adds # to # variant can roll higher then the to spells one)
4 - Any other mod that increases damage if you can't get something out of the top 3
Suffixes
1 - Increased cast speed
2 - Increased (fire) damage
3 - Any other mod of your fancy

Other items
All other items are very straight forward and do the same.

As always the first thing you need to do is cap your resistances, preferably your chaos resistance as well as this would otherwise be a weak spot in the build.
Second is to get as much life and energy shield as humanly possible.
Third are the rest of the stats and those are free game, any sources of minimum frenzy/endurance charges, immunity's, increased damage, triggering things like unnerved or curses, what ever works to get more damage, more defenses, or better quality of life.

Some hints to get you going:
- Gloves can be upgraded with searing exarch / eater of worlds implicit's to unnerve and expose enemies or could be corrupted to apply curses.
- Warlord influenced ring can roll curse enemies with flammability on hit
- Chests can roll various + level of socketed gem variants
- Amulets can roll + 1 level of All skill gems and + 1 level of fire skill gems.

Anoint
What ever you want, If you are not on maximum frenzy charges then "Disciple of slaughter" will be one of the highest dps boosts. You could also go for "Whispers of doom" to apply an extra curse which could be used for more offense, defense, or utility.

Important life and energy shield scaling note
To prevent either your life or your mana/es to run out before the other one does we try to keep both pools at the same ratio as our damage taken from mana before life conversion.
Also having a lot more energy shield as having life while at 50% or lower conversion just means your life would run out before your energy shield is gone so stacking to much ES would be a bit of a waste.
Realistically I'm guessing you could get around 3k unreserved(effective) life with gear that has high (t2) life rolls and boost it to 3500 or so. You'd want your energy shield to sit about 200 to 300 above that so that you compensate for having to spend ES on skill costs. Any more than that doesn't add to much as your life would just run out before your energy shield would anyway.

We get our 50% converted by either using a watchers eye that grants 10% when you use clarity or by using the forbidden flesh/flame jewels to get the Divine Guidance ascendancy. The Watchers eye is my preferred means of getting that extra 10%. If you do have acces to a lot of energy shield though you could go for both options so that you get 60% of damage taken from mana(es) before life.

In case you are not running on a 50% rate do keep in mind to balance your life and energy shield at the same rate as your conversion.
For example, if you'd aim for 10k ehp and you have a 40% conversion that would mean 60% of the damage would be taken from life so you'd want to be around 6k unreserved life and 4k es in this case. The reason you'd want your life and energy shield to be balanced in the same ratio as your %of dmg taken from mana is that once your energy shield is depleted you'd take the full 100% of the damage on your life and will die really fast. The other way around, if your life pool is lower then the ratio that means you will run out of life before you run out of energy shield and die. To prevent either from happening you want to aim for both of them to reach 1% at roughly the same time (not 0 cus we wanna live) The reason I aim for 50% (or higher) because that way your regeneration and life recovery is nicely balanced between the 2 and fully utilized that way.

Another thing to keep in mind is that once your ES reaches 0 you can't cast anything as your ES was your mana and that's now gone. Another reason to keep those ratio's in balance :)

While gearing is easy on this build it helps to understand how the stat scaling works and where there are potential hidden benefits.

Area of Effect
At first glance this just straight up increases the radius of your Brand and Firestorm. Pretty straight forward. For map clearing we don't care to much about the size of Firestorm but your clear speed notably increases as your aoe radius does. As our spells only deal AOE damage any kind of increase to area damage scales just as other sources of of increased (fire)damage would. While AoE does increase consecrated ground effects created by skills it does NOT increase the area dropped by our ascendancy so having Zealotry helps with this on bosses.

Spell effect duration
The build does not have great access to increased duration but it is a nice stat to have if you can get your hands on it. It causes your Brand to both have longer attached times but it also can also linger longer on the ground. This means you have to spam it less frequently on bosses and that's a nice QoL
It also lets your Firestorm's effect of bombarding a area last longer and so in the cases where you only use it to proc stuff that is a nice bonus too.

The longer duration does also seem to increase the time your consecrated grounds stay on the ground but I could not confirm this yet. It does not increase the time it lingers.

Critical strike chance
As our crits do no extra damage due to Elemental Overload it's not an entirely wasted stat. EO does require you to crit at least once every 8 seconds to maintain a 100% uptime and I noticed that it would reach this point between 7% to 10% chance to crit. It should get close to this point without any investment but it's worth to pick up some to boost your crit if you are not at these levels. There is no need to get more then this as it wont add anything after you reach 100% EO uptime.
Crit multiplier is completely useless so no need to get that

Regeneration leach and recovery
In terms of priority life regeneration per second or increased regeneration rate are the most important recovery stats as this is what our build scales with the best so they provide the best value per point.
This doesn't mean that the other stats are bad though.

What you do need to keep in mind is that the Pious Path ascendancy only applies to our life regeneration so all other sources of recovering life won't be applied to our energy shield as well. These other sources include recoup, leech, life gain on hit, etc.
Another thing to keep in mind is that increases to energy shield regeneration do NOT scale off the regeneration provided by Pious Path but instead scale off our base ES so are apart from only being active on ES they are also less effective as what life regeneration would be.

If you can easily get some life and energy shield leech then that would bring in a nice bonus on the already high recovery but it isn't really needed.

Cast speed
The clearly visible advantage to cast speed is that it makes our Firestorm cast quicker so that the time we stand still is reduced. This also applies to Brand recall but that is a quick cast already. For Firestorm however while PoB might say cast speed increases the Firestorm dps a lot, in reality there wont be many occasions where we actively spam Firestorm to such an extend that we'd use that cast speed so for Firestorm the benefit is mainly shorter cast times.

For Armageddon brand it does considerably boost our damage so it's a good stat to have there but there is a thing to keep in to consideration.
Cast speed increases how often the brand activates but effectively there is no difference between it activating 5 times over the course of the duration or 5.99 times. In both cases it's not 6 so you'd get in 5 hits. It also depends on the duration. To get more activation's per brand you can either get cast speed, duration, or both. As it's so flexible I cant provide exact numbers but if you are close to being able to pull off another activation it might be worth getting some extra cast speed or duration.

First go to Sanctuary + Pious Path leaving Augury of Penitence as third. The fourth ascendancy doesn't do to much for us here and I took Instruments of virtue as that gives Battlemage which allows us to roll either + added damage or + added spelldamage on staff. The added damage (melee) is a bit cheaper on a caster staff as most would regard that as wasted stats, it also rolls higher. It's only a small boost though so taking Righteous providence for the +50int + str could also be a option.

We can switch to brand + firestorm at level 28 but I like to do so at around level 32 / 36 as by then we should have the base of our talents done.
As you can't use brand skills or Firestorm before these levels anyway we can wait with getting the corresponding brand talents until we reach somewhere around level 30. We do want our tree to be close to those talents at that point so that we can take all those brand talents a few levels before we switch from our starter setup to brand + firestorm.
I suggest following the trail from "Sanctity" up to "Retribution" and then go to "Amplify". From there I take "Purity of Flesh so that my early game health needs are covered. From there I move in one straight line to "Blast Radius".
Around this time you can start working towards the brand talents, the order here does not really matter as long as you get Rune binder at the point you actually start using the brands. After this I take "Explosive impact" for the final AOE increase. From here on I take "Sovereignty" and start my way down to the "Hearty" talent for the extra regen and take all the life nodes on the way. Once you have that it depends on the gear you have to determine if you need more dps or more survivability

The play style is very straight forward and suitable for both experienced and beginning players.
You just run around and toss a brand at each pack you see.
With a maximum of 7 brands and with the damage they deal individually you wont even need brand recall. Just run around and drop brands in area's where you want mobs to die. Fun thing is that the area's overlap so multiple active brands in a single area means more damage.
If it somehow happens that (some) particular mobs don't die then you can drop more brands in that area so that 2 attach to them or if they seem to be a boss or otherwise tough bastard you can start dropping some Firestorm meteors on it's head.

The branding part is really easy and you'll get the hang of where to drop them and how many in no-time at all. It's also very forgiving and unless you place the brand like a screen away from a mob it will find a target on it's own. Good targeting only makes the havoc ensue a little faster.
Firestorm on its own is a tiny bit more tricky as it's a slow cast that will stop you in place for a bit longer then the brands would but nothing to serious. However if you use Firestorm at the moment a lot of nasty stuff comes flying your way then you'd better be prepared to take those hits as you'll be just a little to slow to properly dodge it but you'll get the hang of that very quick as well.
The hardest part, for as far as it can even be called hard is to get the hang of how and when to use Firestorm on boss fights while keeping 2 brands up.
Keeping the brands up is easy, just 2 quick taps so the brands are up there and they will do their work for a few seconds. From there it depends on the boss on whether or not you are going to spam Firestorm in the meantime or just place a tactical one so that the ignites and other debuffs get going. Good part about this is that Firestorm also lasts for a second or 2.

We kill all.

Major
Here we take "Soul of Arakali" so that the damage over time we take gets reduced by 10%. According to PoB this also counts for our Petrified blood but I have not been able to check if this is actually true yet. If it is that means that it will prevent 5% of the damage to our life and 5% of the damage to our energy shield which is quite significant. Even if it doesn't work like that it will still reduce the damage we take from bleeds, poisons, and most importantly, our own righteous fire so even without PB it's still the best in terms of damage reduction

Minor
Here we take "Soul of Shakari" and upgrade it with "The Restless shade" as soon as we can to reduce chaos damage taken.

There is no mandatory enchantment here. The fire penetration one for Armageddon brand adds the most flat damage.

Mind over Matter only becomes useful once you have Eldritch battery and actually is a bad thing to take before that so do not take MoM before you get EB. Why is it bad before? well, we don't scale mana so together with the mana we reserve for aura's it would mean that you are out of mana constantly.

Does our survivability not suffer incredibly if we dont take MoM though?. Not really, before we make your ES protect mana it will still be there and protect your life so in terms of effective hit pool it wont matter to much. The main reason split incoming damage with MoM is so that we make maximum use of both "Petrified blood" and our combined regeneration of life and energy shield.

The other skill we do not take right away is "Petrified Blood"
We take "Petrified blood" after our second ascendancy and once we at least have some energy shield going. The reason we do this is because PB applies a portion of the damage as a damage over time effect which prevents energy recharge to kick in. Without the Life/ES regeneration Pious Path would give you that would just cause your ES to run dry every time.

Deadly modifiers
Monsters reflect elemental damage - This will kill you once you hit them
Players can not regenerate Life (or energy shield) - Since our defenses are basically built entirely around this it would mean a death sentance

Annoying modifiers
Any modifiers that reduce life or energy shield regeneration but do not prevent it completely are quite annoying. You can still run the maps but you'd be risking a portal or 2 if you don't take it a bit slower.
Also modifiers that reduce your aoe or spell duration are annoying and will impair your clear speed a bit

Modifiers that don't do anything
We are immune to curses and ailments so any modifiers that make you get those things are nice to roll as they will increase map rarity/quantity but wont affect you in any way. We also don't use mana so any modifiers to that are good as well.

Reduced or prevented life/es leech is no big deal either