Level 100 Crit Tempest Shield Occultist^3.28

Notes

IMPORTANT NOTES:
- REFER TO LOWER INVESTMENT GEAR / TREE AND UPGRADE FROM THERE; YOU DO NOT NEED GEAR AS CRAZY/PERFECT AS MINE
- For rares, T1 life (and ES on gloves/boots) is your #1 priority stat, then make sure to cap resists and fulfill attribute requirements with high tier suffixes; mix and match
- Runegraft of Treachery, Witchmark, and Stabilty are MANDATORY. Runegraft of the Sinistral and all tattoos are not mandatory, but are very VERY strong

BACKGROUND:

Life stacking can be very powerful - with Rathpith Globe and Unlight Silhouette on the Nameless Bloodline your damage scales semi-cubicly with your maximum life
(flat damage, % damage, and crit) in addition to the obvious benefit of being very tanky from that enormous health pool. The downside is that both the Nameless
Bloodline and Rathpith Globe cause you to spend or sacrifice life to cast the spells that benefit from that scaling.

However, there is a workaround to those downsides. If you had a hit-based spell which when cast, turned on and then stayed active without being recast, you coul
give that spell a large life cost without worrying about having to actually pay that cost more than once.

Do any spells like this actually exist? There's two, actually.

Bladefall of Trarthus (BFoT) is turned on when cast and then spends mana over time to keep its effect active. Unfortunately, BFoT isn't a practical option because
it spends mana/life over time. You can give it a flat life cost, but if you then try to scale that cost to maximize the scaling from Unlight Silhouette, you'll VERY quickly
burn through your mana and life pools trying to upkeep the over-time costs.

This leaves only one remaining option:

TEMPEST SHIELD:

Yes, that Tempest Shield. It's intended to be a passive buff that gives you some additional chance to block spell damage and the player base almost exclusively
uses it for that alone. However, it also passively deals chaining hit damage to enemies when you block their attacks or spells. That passive damage means we can
take advantage of life stacking mechanics without being affected by  their downsides. You're free to scale the life cost of Tempest Shield up to almost 100% of your
max life and you only have to pay that cost once, when you turn it on.

We can also force the "when you block" damage on Tempest Shield to occur by using Monastery Bell. This unique causes you to activate all of your on-block 
effects the first time you hit an enemy with a shield attack. So, we can use Shield Charge to both move around and hit enemies, activating our damage from Tempest
Shield. Since Shield Charge is an attack, it does not activate the sacrifice effect on Rathpith Globe. You can use Shield Charge as fast as possible, activating Tempest
Shield's damage with no downside. Additionally, while Monastery Bell activates the damage on tempest shield, this is not a TRIGGER, so again, you do not activate
the sacrifice effect on Rathpith Globe.

The downside of Monastery Bell is supposed to be the "unlucky block" line, but that can be turned into an upside using Runegraft of Stability. This causes your lucky
or unlucky effects to instead be rolled three times, picking the middle value. Without getting into the weeds on the math, this is a mini-Svallin effect. It turns our
(attack/spell) 78/78% sheet block chance into 88/88% effective block chance.

You now have two sources of damage from Tempest Shield, making this build surprisingly efficient:
  (a) the damage that occurs whenever you block an enemies attack/spell. From what I can tell, there isn't an internal cooldown on this damage meaning that the
        frequency of this damage scales with the type of content that you're playing. For example, in very dense breaches with large pack size, you get hit extrememly
        frequently and all these hits activate this damage, provided you have high block chance.
  (b) the damage that occurs whenever you first hit an enemy with Shield Charge (using Monastery Bell). The frequency of this damage depends only on your
        attack speed with Shield Charge. You can therefore use a seperate 4-link to get as much attack speed as possible on Shield Charge which ends up scaling the
        hit frequency of Tempest Shield without taking away from "% more damage" support gem slots in your 6-link.

So, the core of the idea is as follows:
1- Stack as much life as possible through the usual means (Apostate, Adorned + magic jewels, life masteries, etc)
2- Get spell damage and crit chance with a volatile vaal orb'd Rathpith Globe (over 900% increased damage and capped crit chance with 15k life)
3- Use Tempest Shield as the source of damage to sidestep the Rathpith sacrifice effect from taxing our recovery (freeing up recovery for more damage with Righteous
    Fire or just to be tankier)
4- Scale the life cost of Tempest Shield to get flat chaos damage with Unlight Silhouette (>3700 flat chaos damage with a 13.8k life cost) while only having to pay that
    skill cost once
5- Activate the damage on Tempest Shield by using Monastery Bell and Shield Charge, scaled with a bunch of attack speed (Essence of Insanity gloves, Runegraft of
    the Sinistral, Faster Attacks Support, etc).
6- Be virtually immortal with the combination of a large hit pool from life stacking, pre-hit recovery with Defiance of Destiny, 88/88 effective block, and % life regeneration.

It turns out that the above are actually pretty straightforward and just require some currency. Except for #4.  #4 is....complicated.

LIFE COST SCALING MECHANIC:

Tempest Shield ordinarily has a mana reservation but no life or mana cost. We can give it a base life cost with Runegraft of the Witchmark and then want to scale
that life cost as close as possible to our maximum unreserved life (without going over) to get the flat damage from Unlight Silhouette.

Support gems on Tempest Shield give % more multipliers and increase the life cost resulting in more flat damage, but they ALSO increase the mana reservation.
This creates a problem with scaling our life costs. The base life cost is 8% of maximum life (Runegraft) but the base mana reservation is 25% of maximum mana.
Any scaling via gems will run us out of mana reservation room before we get life cost to near our max life. To solve this you need either:
   (a) a TON of increased mana reservation effeciency (like over 170%)
   (b) a way to scale up skill costs independent of skill reservation

There are plenty of sources of "% increased mana cost of skills" on both unique equipment and the skill tree. However, this is not useful for us as we need to scale
life costs, not mana costs. There are only two sources of skill cost scaling in the game that don't specify "mana cost": Jiquani's Potential and Indigon. Jiquani's
Potential is not an option - it's a staff and that precludes use of a shield. Since this is a life stacking spell build, Rathpith Globe is absolutely necessary. Therefore,
the only option for scaling life cost is via Indigon.

The relevant stat on Indigon is "(50-60)% increased Cost of Skills for each 200 total Mana Spent Recently." For a moment, assume we can consistently spend
between 100 and 150 mana per second, no more and no less. "Recently" is the last four seconds so this gives us exactly two "stacks" for Indigon. With a maximum roll
on the "increased cost" line of our Indigon, we get a 2.2x multiplier to Tempest Shield's life cost, and therefore its flat added chaos damage, without affecting its mana
reservation.  If we then proceed to pick up a few good sources of mana reservation efficiency, we'll be able to keep the reservation of Tempest Shield below 100% of our
mana pool while scaling its cost to near 100% of our life pool.

Now the question is how to ensure that we're consistently spending an appropriate amount of mana to get two Indigon "stacks". Bladefall of Trarthus re-enters the picture.

BFoT has a base mana cost of 5% of maximum mana per second, scaled as usual with gem multipliers and increased costs. We're aiming for two Indigon stacks, a 2.2x
cost multiplier. With scaling from a support gem and the life mastery, the final mana spend on Bladefall of Trarthus is 12.26% of our maximum mana per second. With
about 1100 maximum mana, this makes us spend about 130 mana per second, almost exactly in the middle of the 100-150 mana envelope that we need to be in to
sustain Indigon stacks.  With this balance of mana costs, at a steady state Bladefall of Trarthus will indefinitely sustain two Indigon stacks without ramping up or down.

It should be noted that the steady state mana costs assumes you ALREADY have two Indigon stacks. To get those initial stacks, you have to jump-start the mana spend
which can easily be accomplished using Arcane Cloak which is hard-coded to spend 45% of current mana at level 1. With our ~1100 mana, this is 495 mana, giving us
two Indigon stacks immediately which can then be sustained by BFoT.

You need to restart the life cost scaling "loop" at the beginning of every map or Mirage, jump-starting mana spend to get two Indigon stacks which puts BFoT
cost-over-time at the appropriate amount to sustain the Indigon stacks indefinitely. The default state when you enter a map is Tempest Shield on and BFoT off. I've
settled on the following procedure which takes about 5 seconds but is very repeatable. After a bit of practice, I got the muscle-memory down and can accurately
start the loop with near 100% success rate.
1- Enter the map
2- Deactivate Tempest Shield (unreserving all of your mana)
3- Wait 4-5 seconds for mana to refill (or pop writhin jar flasks)
4- Activate Arcane Cloak (giving two Indigon stacks)
5- Immediately activate Tempest Shield (reserving mana and spending almost all life)
6- Wait a brief moment (less than a second), then activate BFoT

This works almost 100% of the time to sustain 2 Indigon stacks. If you do step 6 too fast or slow, you will end up with 3 or 1 Indigon stacks instead of 2. You can check
that you did the process correctly by hovering over Tempest Shield on the skill bar and verifying that its skill cost is just below the your maximum unreserved life.

Putting it all together, our life cost and mana reservation are as follows:
                              |  Base  | Gem Multiplier |  Increased Cost (61% Indigon)  | Reservation Efficiency |                  Total
              Life Cost  |    8%   |     x5.1105       |                    x2.22                      |                                     |   90.76% of maximum life
Mana Reservation |   25%  |     x5.1105       |                                                   |           x0.7246             |   92.57% of maximum mana

Perfect. We've scaled our life cost to a large portion of our huge life pool but left some room to reserve life for Clarity, Vitality, and Precision. We've also kept the
mana reservation below 100% with some room for comfort. (You want to be a bit below 100% so you can walk through a mana siphoner bubble without turning
off BFoT.)

THE PAYOFF:

The payoff is Tempest Shield dealing an average hit of over 5 million damage. This is activated more than 5 times per second (the attack speed on Shield Charge +
Monastery Bell is 5.64 aps) plus the passive activations from blocking. All told, Tempest Shield ends up dealing at least 25 million damage per second, or significantly
more in dense content. The build is also nearly immortal with the large life pool, 88/88% block, Defiance of Destiny pre-hit recovery, and % life-based regeneration.
Even the Uber bosses were taken down with ease. I've even cleared some of them entirely AFK.

This was my end-of-league project for Mirage and was far more successful than I expected. It uses imbued gems and some Volatile Vaal Orbed uniques, but that's just
for min-maxing and is not required so this build will quite likely continue to function in future leagues with only minor adaptations. I don't consider any of the mechanics
used here to be bugs; they're just niche combinations of expected behaviour so I expect the mechanics to be immune to patch notes.




BUILD NOTES:
This is a life stacking build. Scaling life gives us:
- % increased damage (Rathpith Globe)
- flat added damage (via life cost; Nameless Bloodline + Runegraft of the Witchmark)
- critical strike chance (Rathpith Globe)
- hit pool
- recovery (Defiance of Destiny recovers based on missing max life)
Life is the #1 priority on every piece of gear.

- REFER TO LOWER INVESTMENT GEAR / TREE AND UPGRADE FROM THERE
- % reservation implicit jewels not necessary; drop Mystic Bulwark, take Sovereignty wheel instead; lose a couple passive points
- careful of implicits or enchants on Apostate which brick the life mastery
- unwavering stance is optional, but HUGE quality of life
- If you want to run reflect maps, get Prismatic Skin wheel / Protection mastery (max fire res pathing, and switch a jewel suffix to crit) + Yugul Pantheon
- additionally can craft a Hunter or Essence of Insanity ring to drop protection mastery, saving a passive point (or four if you drop the whole wheel)
- need endurance charge generation: either a Rote Reinforcement megalomaniac or take the Inexorable wheel; Rote Reinforcement is better
- Runegrafts are mandatory, tattoos are not

FAQ:
Dissolution of the Flesh gives 30% more life, that should be good.
   - Not an option. Even though we're not spending life, we still need to be able to afford the life cost for Unlight Silhouette. Dissolution will reserve life, making our cost
     higher than our unreserved life, and bricking the added flat chaos damage
Is this like Cast When Stunned where you have to wait to get hit before you can deal damage?
   - That's what Monastery Bell is for. It lets you proc the damage from Tempest Shield when you hit with Shield Charge.
Monastery Bell has "block chance is unlucky" - isn't that bad?
   - Nope, Runegraft of Stability turns that into a mini-Svallin. Effective block chance is 88/88% attack/spell.