To coc or not to coc - that is the question

chest:


I was thinking to dual wield: Piscator's Vigil - and just try to corrupt it for culling strike. Although its not the obvious choice (in my eyes) for coc build, i do love the this wand, and they are dead cheap ;)

A few adjustments to passive tree + reasoning:

tree

- you really want the Melding cluster + an energy from within jewel if you're gonna play a CI build
- Primal spirit and Finesse are excellent - they give you mana, strength and dex, attack speed and accuracy - you will want and need all of these
- Doom Cast and Annihilation are way too good to skip
- removed the aura cluster, you won't need it with the setup I'm going to recommend
- took two more jewels, jewel sockets are extremely good for this build in endgame. You can easily find jewels with three damage-increasing stats and even jewels with four if you are willing to pay well. Ways to scale damage with jewels: phys dmg, spell dmg, global crit multi, spell crit multi, attack speed with wands, attack speed while holding a shield, attack speed
- selected passive point instead of phys dmg from bandit reward - this build is point-heavy and I would personally opt for the flexibility of one more passive point, also a large portion of your damage will be elemental
- switched over from Assassinate to Toxic Delivery. Reason: first off, when you hit something with barrage and it procs CoC, your target is no longer on full life. You will also have a capped 95% crit chance with barrage, so Ambush will be wasted anyway. About Assassinate, it sounds good in theory but in reality you will oneshot everything apart from map bosses and you will kill even map bosses so quickly, you won't actually feel its effects. Toxic Delivery, on the other hand, will sometimes be felt. The barrage hits will apply bleeds, and then EK and Bladefall will have a chance to apply a super-buffed poison which deals a lot of damage. You can, for example, hit a boss once or twice and kite it while it dies from the poison. In the end, these are just details and the Assassinate route also works almost or just as well. Just a matter of preference, really.

Now, about the build itself:

6-link setup: you will have a big fucking problem there. My setup uses 5 green slots. Getting 5 green on a vaal regalia is next to impossible and will cost you many exalts in chromatic orbs - if you're lucky. A compromise would be to just use a different setup - perhaps replace bladefall or chain with arc. This will probably slow down the clear speed but it should still be good. Getting 4g on the chest armour will still be tricky. I would probably go with barrage level 1 (to keep mana cost down) - CoC - chain - arc - bladefall - controlled destruction.

other gem setups:

(3L) hatred + herald of ash + enlighten
(3L) herald of ice + curse on hit + assassin's mark
- the idea of this setup is to maintain your power charges. When you kill a pack, mobs explode with HoI and curse their neighbours with ass mark milliseconds before they explode too. What this does in practice is keeping your power charges up between packs.

Now, this will leave you with hatred, HoA and HoI and something like 97% reserved mana. Since the build is intelligence-heavy, your passive mana regen will be enough to sustain barrage for 2-3 attacks on its own. What you are going to do is get a jewel with +2 mana gain on hit. Just that, combined with the mana regen, will be sufficient to sustain your barrage without any issues.

(4L) cwdt lvl 1 - ice spear - GMP - PCoC > this is your third power charge generator besides from the assassin pasive and the curse on hit HoI - ass mark

(4L) cwdt lvl 1 - warlord's mark - increased duration - immortal call
- what this setup does is ensure you some leech and give you almost a second against phys reflect mobs, which doesn't sound as too much but actually helps a lot

Now, this will leave you with one unused 4l setup of your choice. Bear in mind that your unreserved mana will be very low, probably around 40-50, and will make a lot of spells unsustainable. I personally used flame dash for movement and another lvl 1 cwdt setup with a golem and I forgot what else, but you can choose something else.


Gear:
- Piscator's is like an entry level wand at day 1 or 2. I found a much better wand at day 3 of Prophecy league. It gives no spell damage, spell crit or crit multi. This makes it a super-budget solution and nothing else. What you want is a wand like this:
http://poe.trade/search/ezaukoromiuitu
or this: http://poe.trade/search/ohenasariniuke

As for dual wielding, I strongly recommend using a high-ES shield instead. The shield is the second most important source of ES and damage will be more than enough anyway, no need to compromise that by dual wielding.

About accuracy, you need 250 or more on two items out of 3 possible slots: 2 rings, helmet. I assume the amulet will be Eye of Chauyla.

Helmet: what I did was buy an ilvl84 hubris circlet with the 2 additional barrage projectiles enchant and chaos spam it until I got something satisfactory (it was life, accuracy and resists for my build, you'll want ES and accuracy).

Gloves: facebreakers rule here, no contest

Boots: good rare ES boots or Brineror Whalers

Dealing with reflect: atziri flask + taste of hate + the immortal call setup. You'll sometimes hit offscreen reflect mobs which will be impossible to pre-flask but you shouldn't oneshot yourself in them. I didn't at 4800 life and you'll have quite a bit more ES. Of course, the safest option will be a lifeleech gem but I don't think you'll want that, it's another offcolour in an already way too offcolour-heavy 6-link setup.

Now, all of this was written in a hurry and I may very well have missed something. Regardless, it should at least give you some ideas.