Level 100 Caustic Arrow Pathfinder^3.23

Notes

BANDITS & PANTHEON:
Bandits: Kill all
Major God: Soul of Arakaali
Minor God: Soul of Ralakesh

AFFLICTION LEAGUE:
You'll likely want to start with the Warden of the Maji ascendancy for Barkskin and Nature's Concoction to substitute either your Gold Flask or Witchfire Brew for a Tincture next to Divination Distillate. Later on in the league, Wildwood Primalist will likely be the superior ascendancy.

LEVELING:
Follow the early leveling trees and use the Skills and Items section under 'Poisonous Concoction LEVELING' to gain an idea of how best to outfit your character as you progress through the campaign and into maps. This includes a mix of rare items and extremely cheap uniques (uniques for early leveling isn't necessary).
After killing Hillock, choose between with Galvanic Arrow or Caustic Arrow as your primary damage ability. Use this until you unlock Poisonous Concoction at the end of Act 1. You'll want to use 'Chance to Poison support' until you're at or near poison cap. Otherwise, attempt to match the links up to the guide's recommendation.
As of patch 3.21, Poisonous Concoction suffers a loss of 30% increased AoE from the Ascendancy and now endures rising life charge cost per projectile per attack. Both of these nerfs are circumvented greatly by swapping the traditional Greater Multiple Projectiles support out for another damage support gem until endgame.
If at any point you find yourself shy on attribute requirements, you can always sacrifice a point or two for the +30 strength/intelligence nodes nearby.
There are two respecs both of which take place prior to maps. These respecs will cost a combined total of 18 points out of the maximum 20 that you obtain in the campaign. The second respec highlights the swap from Poisonous Concoction to Toxic Rain. Preferrably, you'll want to have purchased a Quill Rain prior to making this swap.

LATE ENDGAME:
It's not recommended to swap from Toxic Rain to Caustic Arrow until you have a Widowhail paired with a well-rolled double-dot multi quiver.
Unlike some endgame magic find builds, Inspired Learning and or Headhunter will not have a major impact on this build's performance.

UPGRADING:
Here are some strong but expensive upgrades to consider that go beyond the budget of this league start build guide (in no particular order of importance).
1) Reaching maximum quality on all gems that provide some benefit from it
2) Acquiring perfect or near-perfect rolls on all flasks
3) Leveling and corrupting cheaper gems for a chance at a level 21 gem (priority Toxic Rain, Grace, Malevolence)
4) Swapping damage support gems for their Awakened gem counterparts
5) Squeezing in an Enlighten support and adding an additional aura or Aspect of the Spider
6) Acquiring the corruption "Curse Enemies with Despair on Hit" on Kaom's Spirit, thereby dropping Witchfire Brew, and trading out Voll's Vision for either Fairgrave's Tricorne, The Gull, or a rare helmet.
7) Slotting in basic jewels into nearby jewel slots on the passive skill tree.
8) Dropping points from the left side of the passive skill tree for chaos-themed large and medium cluster jewels.
9) Adding an Inspired Learning to the Shadow side for more player power.
10) Getting Progenesis into your flask lineup
11) Swapping Bisco's Leash for Headhunter (or Mageblood if you prefer)

CHAMPION ASCENDANCY (optional):
For anyone interested in doing this build with the Champion ascendancy, you can keep essentially the same build with minimal changes. Choosing Champion over Pathfinder will result in slightly more speed, moderately more defense, and moderately less damage overall.
1) Take ascendancy points First to Strike, Last to Fall, Unstoppable Hero, Fortitude, Inspiration (in that order)
1) Swap the three starter small passives
3) Swap Void Manipulation support for Withering Touch support in the Focused Ballista link.
4) Rerrange links to drop Vaal Haste & Increased Duration support, pick up Arrogance support and link it to Vitality. Add Petrified Blood. This results in nearly the same mana pool.
5) Recover the lost 30% increased flask effect via the Warden of the Magi ascendancy and Tinctures (Affliction League ONLY) to keep a minimal mana cost on Malevolence