Gameplay Help and Discussion - Damage Advice Caustic Arrow & Poison Gem + Contagion - Forum

While most of the mechanics discussion in this thread is spot-on, I disagree with some of the theory presented here as someone playing CA right now.

Firstly, while Rapid Decay and Void Manipulation are indeed the top two damage supports for CA, I disagree strongly with the use of Concentrated Effect, and I believe that Increased AoE should take priority over Void Manipulation in a 3-link (CA is solid leveling these days with the huge buff to low-level damage the skill got in 2.1). Having more coverage for your CA is amazing, and makes it easier to take out entire packs with one arrow instead of having to use 2 or 3 to get full coverage, particularly in indoor maps if your Pierce chance is low.

Second, while Slower Projectiles is indeed a "more" multiplier, it's such a small multiplier that Pierce + Drillneck gives a competitive damage boost with the extra utility benefits of higher pierce chance and significantly lower mana costs. You could get a lot of Pierce with a lot of investment from other sources, but the Pierce Support gem gives more than anything and gives it more efficiently than these other sources, IMO.

Finally, a Caustic Arrow build does not need to disregard the Poison skill gem. Afterall, the tree of a Cuastic Arrow build is going to have significant Chaos, Projectile, and DoT scaling, and the Poison caused by a bow attack will be scaled by Chaos, Projectile, and DoT nodes. There is a conflict in that the initial hit damage of a good Caustic Arrow bow will be low, but that's why we have a thing called Added Chaos Damage.

My current character is using Barrage + Added Chaos Damage + Poison + Void Manipulation + Faster Attacks in her chest armor, gems are level 18 and 19 with no quality. At level 79 with my build, this is giving me as much as 20k single-target DPS with this bow:

Thanks to this setup, this not only melts bosses but completely removes the need to use Conc Effect on CA (which was previously only used because poison wasn't good enough to use as single-target damage).