[3.10] Ewpewww's 'budget' CoC Arc Herald Stacker - >10 mil shaper DPS for as cheap as ~15ex

Some disclaimers before we go into the guide proper:
- This is a 'budget' version of the build so don't expect any crazy shenanigans like tanking Sirus storms or one-shotting bosses
- I did not start my character afresh. I re-used my old Guardian character
- Prices in the budget section mainly an estimation based on prices of items on trade at point of writing this guide (9 May). It is subjected to changes (which I will not update for) based on market fluctuations.
- This is a Cast on Crit version of the build: (1) You can choose to play with other skills / styles (unleash, spell echo), I just really enjoy CoC (and have always wanted to play it). (2) I have not yet optimized for CoC breakpoints (which will give the build more damage but I'm lazy to do so at this point)
- When it comes to fitting in the auras that you want, suggest you play around with POB instead of sticking to this build to a T.. reduced mana reservation can come in so many sources so you have to experiment on your own

T16 Minotaur Speed Clear
T16 Phoenix Speed Clear
Wave 19 & 20 Simulacrum Clear
T16 Canyon 100% Delirious Deathless

Pros
- Allows for herald stacking on a "budget" of roughly 15 ex
- Endless upgrade options for people who would love to min-max (LIKE ME!) - I will include section in later part of the guide about different options for upgrade and what to priortize
- When min-maxed, can easily tank all content in-game incl. Sirus storms
- Pretty high survivability due to 90% max elemental resistance
- CoC allows for a lazy playstyle - SPIN TO WIN

Cons
- 15 ex budget is not for most people - I've tested this and I think you need at least 15 ex to play this build comfortably
- There are a lot of required uniques, which you have to acquire from trade. This build might not be for SSF or those who hate trading
- Budget version can still die to some content, given lack of chaos resistance
- Clear speed is decent but not insane like herald sparkers or EK

This is my interpretation of the ever popular herald stacking build. As all other herald stacking builds, it takes advantage of the OP notable that is Purposeful Harbinger ('PH'). Basic idea:
- You get as many PHs as possible - which gives you 10% increased effect on you for each Herald affecting you
- You stack as many auras as possible through reduced mana reserved from many sources - Wrath, Hatred, Zealotry for damage; Haste for QOL; Purity of Ice, Purity of Fire, Purity of Lightning, Discipline, Vitality for surviability
- Profit!!!

Contrary to other herald stacking builds I've seen, I think priority for the build is to stack as many PHs as possible (up to 9). This means we will need 3 Voices (unique cluster jewel) for the build as opposed to 2 socket large clusters that others are recommending for budget build. (I have seen a fair share of people coming to my stream telling me that is not working.) The marginal benefit of PH is just so high that we shouldn't pass it off. Anyway, at time of writing, 7 passive voices are going for ~1ex (which is rather affordable).

We overcome low cast speed of Guardian builds by using Cast on Critical Strike Support. For those not familiar with CoC builds, we can cast linked spell (arc) every time we deal a critical strike. We use cyclone as the skill to trigger CoC because it has a very high base attack speed.

Key aspects of the build in numbers
Defensive numbers

Offensive numbers

Required Keystones
Pain attunement, Zealot's Oath

https://pastebin.com/A9VMA14q

Why stack heralds?


Ok.. so how do we get 9 Purposeful Harbingers?


Sounds good.. so what auras do we need?


Right.. but I don't have enough mana reservation..


Ok.. but I heard these cluster jewels are really expensive.. Is it really a budget build?

Link to skill tree (without cluster jewels)
Not shown on passive tree:
- In the three large jewel sockets, you put 3 Voices, and 9 medium cluster jewels with Purposeful Harbinger.
- You take Charisma and the pass for 'Reduced Mana Reserved' next to it using an Intuitive Leap jewel.

There is a lot of debate over Scion vs. Guardian. My view is the following:
- Benefits of going Scion are as such:
(1) Allows you to take advantage of Necromancer sub-ascendancy for higher attack speed and cast speed. However, this is not required for this build given we can reach attack speed cap easily, even with maximum cooldown recovery.
(2) It provides more passive skills points, which makes a substantial difference if you can fit in another Voices for 12 Purposeful Harbingers. That requires insane amounts of budget which defeats purpose of this build

That said, I am not against going Scion - in fact I have a level 100 Scion herald stacker :D

My opinion is that Guardian is the cheaper alternative to the build because you can still be fairly tanky without those insanely costly Purposeful Harbinger + Replenishing Presence jewels.

Ascendancy order as such:
(1) Radiant Faith: Gives you ES + Armour
(2) Unwavering Faith: Gives you Phys damage reduction + Life regen (both are key to defensive mechanics of this build)
(3) Radiant Crusade: For 10% more damage and Onslaught (sometimes)
(4A) Harmony of Purpose: For free charge generation
(4B) (Alternative) Bastion of Hope: For block (if you intend to employ block as another layer of defence)

Good job if you've already made it this far! :D
Now.. to the most exciting reveal of the build. How do we keep it budget?

This is how much in total I've spent for the build (not incl. miscellaneous stuff like skill gems, and other items worth <10c)


First, we have to understand that the most expensive parts of most herald stacking builds are:
(1) PH cluster jewels


(2) Reduced mana reserved base / abyss jewels


(3) Reduced mana reserved + Vitality Amulet (which requires awakener craft)

Almost all of these are required uniques for this build to be this cost efficient (except belt and boots):

Weapon


Shield


Helmet


Body armour


Gloves


Boots


Amulet


Belt


Rings


Flasks


Jewels:

Main skill (in order of priority):
- Cyclone
- Cast on Critical Strike
- Arc
- Inspiration (important for mana reduction.. if not you will run out of mana)
- Cold Penetration
- Energy leech

Shield:
You want your costliest auras here to take advantage of reduced mana reserved from Prism Guardian:
- Wrath
- Hatred
- Zealotry

Helmet:
I want to take advantage of +2 to socketed aura gems in Alpha howl for more defenses and higher crit chance:
- Discipline
- Vitality
- Precision
- Blood Magic

Other auras:
Where you place them doesn't really matter so just optimize for wherever you can get the right socket colors:
- Herald of Ice
- Herald of Thunder
- Herald of Ash
- Herald of Purity
- Herald of Agony
- Purity of Ice
- Purity of Fire
- Purity of Lightning
- Haste

Other skills:
- Smite (I put in weapon since my weapon has +1 to socketed melee gems)
- Dash (for movement speed)

Bandits: Kill all, we want all the passive points we can get.
Pantheons: Soul of Brine King to deal with stuns. Soul of Shakari for poison immunity (which we need given low chaos resist)
Enchantments: None required.. Ideal would be elemental penetration if you haven't killed. But, there are many other things to upgrade before this

Please see first comment of the thread below - there is a dedicated section on this.

There are a few map mods that make things tricky for this build:
- Elemental reflect: I run them with sextants or simply roll over them
- No regeneration of life, mana or energy shield: This makes the map rippy because we cannot regen energy shield. Also, makes it really annoying because you can't regen mana. If you want to run it, suggest you swap out cold penetration gem with mana leech, and minimze use of movement skill (dash in my case)
- Less recovery rate of life and energy shield: This makes the map rippy as well but usually still doable - just be more careful.

I strongly advise against levelling as a herald build.. Purposeful Harbingers only come online when you have a critical number (7-9 of them).

Since the skill tree for this build is going to be significantly different from most builds, you will eventually have to respec anyway (prepare lots of regrets). This means that you can almost level as Templar builds:

- Totems: Freezing pulse, arc
- Brands
- RF

The way cast on critical strike works for this build is as such: Everytime you hit a critical strike with cyclone, you cast a linked spell. However, there is an internal cool down in the CoC support gem. Basically, without any cooldown recovery, you can cast a arc a maximum of ~6 times. Therefore, going above 6 attack per second ('aps') is not going to add significantly more damage for the build, except damage that you get for cyclone (which i think is negligible).

With cooldown recovery, though, we can increase the cast per second of CoC but it operates in a rather strange way of 'breakpoints'. My interpretation of it is as such:
- Casts per second does not scale linearly with cooldown recovery speed
- Casts per second only increase when you hit certain levels of cooldown recovery speed. Based on my understanding, 15% and 52%. These are known as breakpoints.

To get to the following cooldown recovery speed:
(1) 15% to get up to 7.5 casts per second, you want <7.5 aps - use either cooldown recovery on belt or boots
(2) 52% to get up to 10 casts per second, you want <10 aps - use awakened CoC gem (at least level 4 for 19%), and cooldown recovery speed from boots (up to 15%) and belt (up to 20%)

What does this mean for the build?
- Ideally, you want to maintain an aps that corresponds to the cooldown recovery that you can get
- The POB/my character posted is certainly not a good example of that - it definitely can be optimized to do more damage but I got lazy :P
- In terms of what you can tweak to get to the right level of attack speed:
(1) Haste gem level
(2) Removing increased attack speed from your jewels that give you reduced mana reserved
- You should test out your max aps when mapping - remember that it needs to take into account onslaught, frenzy charges

For those who are interested, here is a CoC breakpoint calculator: link

What skill gems should I change if I want to run non-CoC version of the build?
Replace cyclone, CoC, Inspiration with controlled destruction, arcane surge, and Unleash / spell echo. However, you might run into mana issues, in that case you might want to consider running clarity (in place of precision / RF if you are running that)

Are there gem swaps we can do for bossing?
To get even more damage from the build, you can swap arc for wave of conviction, and energy shield leech for phys to lightning. Explanation for gem swap as follows:
- Wave of conviction: This is a physical spell it benefits from the gain x% of physical damage as cold damage mod on hatred (which arc doesn't). It also automatically applies reduced elemental resistance through exposure, which adds even more damage.
- Phys to lightning: To bring phys to lightning of conversion of the skill to 75% so that the lightning damage benefits from Wrath's more lightning spell damage, before most of it is converted to cold damage, which benefits from more cold damage from Hatred

This is my second build guide so please feel free to post any feedback as comments. Thank you!

For helping to experiment with the build!
- MrA7x, Vanqwaffen, chriscknuker, Jayusmaximus, Shahmat2015

One of the best things about Herald Stacking builds (at least in my opinion) is that the upgrade options are limitless. As a result, this can also be confusing for newer players / people not familiar with Herald Stacking build. As such, I would like to share my two cents on the different upgrade options available and how cost-efficient they are. I also welcome your thoughts on them to help improve this guide.

Disclaimers
- Upgrade options are based on this version of herald stacker - the concepts discussed here might or might not be applicable on your character, depending on your choice of main skill / class
- Assessment of cost efficiency will be based on prices at the time of writing. Also, some of it will be based on my intuitive judgement. Highly recommend you play around with POB with regards to these upgrade to see which ones you are most comfortable with.

For simplicity, upgrades will be bucketed into two categories:
(1) Damage
(2) Survivability

I WANT TO DO MORE DAMAGE!!!


I WANT TO TANK MORE DAMAGE!!!


I WANT TO USE A DIFFERENT SPELL!!!

15 ex budget (entry level)


25 ex budget (yay slightly richer!)


35 ex budget (even richer!)


50 ex budget (what is budget?)