Level 100 CI Ball Lightning of Orbiting Hierophant^3.27

Notes

You can swap to any spell that hits. I personally like Ball Lightning of Orbiting as the best allarounder.
The highest single target is Incinerate or Vortex of Projection. Some classics like Spark, Storm call of Ice Nova of Frostbolts also work well. Check Skills panel for setups.
The huge majority of the build's damage comes from Archmage + Arcane Cloak and not the active skill. Area spells work the best because Hierophant naturally gives 100% increased AoE.
If you want to try Spark, get proj tatoos, jewel implicits, faster proj support or a multilink glove for it.

ALWAYS ADJUST mana cost for your gear and picked skill. If you can't sustain, add 1 or 2 reduced mana cost jewel into the build. Reduced mana cost is a legacy suffix on base jewels, and it can also be a Synthesised implicit.
The build has 89% reduced mana cost with a good rolled misted ring, which is enough for most skills, but for example Incinerate needs the 1 extra jewel for nearly 98-99% reduced cost to function.
Don't go to 100%+ reduced mana cost, because Sigil of Power would stop functioning.

Swap your unique flask: Atziri's Promise for DPS, Rumi's Conconction for tank, or Oriath's End for better clear.

Mechanics overview:
All lightning and cold damage is taken as fire via the 3 unique jewels in the build.
Fire resistance cannot be penetrated makes sure 90% maximum resistance for all elements is always active.
Shock, Bleed, Corrupted Blood, Chill, and Curse immunity/reduction from jewel implicits
Stun immunity from abyss jewel implicits + tattoos.
Freeze Immunity from major pantheon Brine King.

Recovery sources:
Regen from flask, consecrated ground from CWDT Purifying Flame, and minor pantheon Tukohama
AR & ES mastery 5% recovery when taking physical damage FOR EACH HIT is massive on huge ES pool, it stacks, it is comparable to %ES gain on block of block builds (Note that PoB doesn't calculate this at all)
ES Leech from jewel implicit
You can do NO REGEN maps if you swap in another mana cost jewel for 0 cost or use a Legacy Vessel of Vinktar for mana leech.
Because of Elemental Overload, we need to get % chance to shock on either TWWT or on the skill tree.

Bloodline ascendancy:
Hierophant nodes are better than bloodline ascendency nodes for all content, but if you are running a lot of T17s then dropping Conviction of Power 
and picking up the Aul ascendency's Precursor's Release node for action speed reduction immunity can be worth.
In that case just use Flame Dash as a movement skill, remove gems from boots, and include power charge generation to get proper crit chance for Elemental Overload!

For maximum tank setup you can swap in Forbidden Flame and Flesh jewels to get Radian Faith, remove Eternal blessing, and use Arctic Armour and Flesh and Stone to reserve most of your mana to gain 100k+ ES, sacrificing a lot of DPS.

Ring choices:
A 3-stat Helical can already beat the best mirrorable ring DPS-wise, and for mana cost too.
Crafting a Misted Helical steps: 
 - Deafening Essence of Spite on a clean Helical Ring base, annul down every other mod until you get a single Intelligence mod. 
 - Bench: Can have up to 3 crafted mods, Suffixes cannot be Changed, and a random filler suffix
 - Reforge Caster at the Harvest bench. This has 33% chance to give you T1 cast speed. Annul if you didnt hit, or rolled a prefix.
 - Bench: Suffixes cannot be changed (while still having the other 2 previously benched mods)
 - Used Veiled Exalted Orb, Unveil for mana+mana cost, if you dont get mana cost annul down the prefix, and repeat
 - Divine looking at the prefix only first, then bench Prefixes cannot be changed, then divine the suffixes too. Add attribute catalyst.
 - Bench Can have up to 3 crafted mods and +1 to minimum Frenzy Charges (chosen because it doesnt hurt if it goes negative)
 - Use Reflecting Mist, will take a few attempts to hit positive on the 3 mods we crafted.
 - You can Vendor 5 failed misted rings for a clean Helical base, just beast split it after, retaining 80% of Helical bases this way (1 clean base becomes 2 after splitting, then 4 after misting both)
Average expected total cost for this is 1-2 mirrors.
Alternative: Mirroring a Synthesised ring: you can see Maeltrom Knot in this pob, which I service with 0 fee, contact at @Markusz for mirror service.
A 5-stat Helical can be made a similar way, but using Hinekora's Locks before every Reflecting mist attempt, but the expected cost to hit 5-positive, is multiple dozen mirrors.

Jewel crafting:
 - Get a Synthesised Cobalt jewel (Viridian or Crimson can also work, rolling is harder) with +5 int, or 3% cast speed while holding a shield, or 2% reduced mana cost implicits.
 - Use Gilded Fossil, then make the jewel magic.
 - Get several of them in a line in a regular stash tab, rebind your mouse scroll wheel to clicking (allowed by ToS, program: X-Mouse), 
    and alteration spam multiple of them at the same time, using a regex to highlight the mods "of intelligence|enlightened"
 - Once you hit, augment and annul until you hit the other mod, then divine it.
 - Use beastcrafting to add a lock on the jewel (costs Black Morrigan+Craicic Chimeral beast).
 - Check Vaal Orb outcome by hovering the jewel, and not clicking. Aim to overwrite the gilded implicit with the Vaal implicit, resulting a 2-implicit jewel.
 - Reset failed attempts with Blessed Orbs, or if cannot be blessed, then use beast craft Imprint. Both imprinting and restoring removes lock, so it costs half a craicic in this case.