[3.0, WIP] Shar, Dark Goddess (EDAE-Chaos Spellcaster, CI-GR-ZO)

The idea behind this build is to build around the "adds xx% elemental damage as extra chaos damage" (to which I'm going to be referring to as EDAEC for short) modifier on some of the unique items.
EDAEC works by adding chaos from every elemental source, even converted one. In this build, for example, we start with Arc Spell, dealing pure lightning damage. We convert 80% of this damage to cold, and then convert this 80% into 40% fire (+10-29% as extra fire damage, but not sure if this applies tbh, so I won't include it in the next calculation).

Let's say we get 20% EDAEC from gear. This results in (100%*0.2) + (80%*0.2) + (40%*0.2) = 20%+16%+8%=44% extra chaos damage after conversions, possibly more if "gain xx% of cold damage as extra fire damage" does apply.

Sources of EDAEC can be found on:
- Atziri's Promise.
- Incandescent Heart.
- Duskdawn.
- Shade of Solaris.
While we could dual wield Shade of Solaris, it means that we cannot go Crit, which is plentiful around Witch starting area and a mistake not to scale it.

While EDAEC scaling is nothing new and there are already multiple guides building around it, I haven't seen one made for Witch yet (granted, I didn't look much), or one that would utilize Duskdawn instead of dual Shades.

Still leveling, but here they are (level 74-75 and 5-link, leveling with Arc gem setup)
Shaped Twin Mesa: https://youtu.be/3WWBsSx0WY4
Canyon: https://youtu.be/K-vkZt1MkHs

BiS weapon for this build, a crazy dps increase. It is a bit pricy, however, but there are some replacements that you might want to look into (from best to worst, dps comparison of Unique staffs - assuming your gems are socketed in these weapons!):
- Duskdawn - almost 80% more dps then Xirgil's.
- Realm Ender - 20-25% more dps then Xirgil's.
- Agnerod West - around 10% more dps then Xirgil's.
- Rare staff with +2 Lightning gems and 80 spell damage - around 8% more dps then Xirgil's.
- Realmshaper - only slightly more dps then Xirgil's (5%>).
- Xirgil's Crank - lowest dps but great defensive mechanic.
- Rare staff with +2 Lightning gems and 40 spell damage - same dps as Xirgil's.


Without these, there is nothing to start conversion cycles, and no extra bonuses from EDAEC. Resists and Intelligence are a nice bonus, but nothing spectacular. Ignore mana regen, using CwC takes barely any mana at all.
Cheapest ones are around 1 chaos, decent stats will be 5-10 chaos.


Ascent from Flesh is a great leveling unique for this build, but you will want to swap to a rare sooner or later. My character isn't res capped at the moment, and my rare Crystal needs a few more levels, so I might buy a Chain belt until I hit lvl 79, or not, not being res capped isn't a big problem yet.
AfF might be expensive early in the league but can be bought later for around 1 chaos, current Crystal belt cost me around 25 chaos.


Rare boots/gloves/amulet is what you need to get necessary stats like Strength and Dexterity, ES and most importantly, resistances.
- You can use Rainbowstride as cheap leveling/end-game alternative to rare boots. My rare boots cost me around 25 chaos.
- Due to not meta stats, amulet cost me only 5 chaos - I only had to remove life craft and put Energy Shield craft for 4 chaos. Carnage Heart is a decent alternative, however, rare amulets will probably be both cheaper and better.
- Voidbringer is a possible and cheapish alternative for rare gloves, however you will struggle with resists which you will have to fill up with jewels, loosing possible damage mods.


Incandescent Heart is a BiS armour for this build. Added damage from this armour is insane, it has ok-ish amount of ES and more importantly, reduces incoming elemental damage by 25%. In essence, finished build at level ~89 with 300% ES from the tree and my current gear will have 7.2k ES, but against elemental damage it is effectively 9k ES (7200x1.25).


Lastly, headgear - here the top options are Doedre's Scorn and Eber's Unification. Depending on chosen skill, the head enchantment can make a big difference - for example, I've had setup a search for Eber's with Arc enchantment going for over a week and a half now, with no results even in offline searches.

Flasks:

Activating Atziri's Promise adds rouhgly 25-30% more dps, so with this flask being so cheap it is a crime not to use it.
Diamond flask also adds a great amount of dps to the build.
The Overflowing Chalice does 3 things for us: Consecrated ground improves our regen / being a Sulphur flask, it adds some dps / and finally, it greatly helps to keep Diamond/Atziri flasks up at almost all times. As a bonus, Chalice has not 1 or 2, but 3 uses.
Quicksilver is a no-brainer since we need to move around a map to get our epic l00tz.

As for the last flask, it can be anything:
- A spare Diamond/Atziri for better dps sustain vs bosses.
- A Basalt for added physical protection (or Granite of Iron Skin).
- Rumi's for extra armour, block, and dps (see Duskdawn).
- Kiara's for stun/freeze/curse immunity.
- If using physical based spells, Taste of Hate or Sin's Rebirth are ok-ish offensive but also good defensive flasks.

Wicked Ward: First and most important point, great defensive node.
Frobidden Power: Offensive node now, Power charge generation is important for any crit build, this one included.

Take those 2 above first, and for the last 2 points, take these 2, depending if you want more defense or offence:
Vile Bastion: Stun protection, but more importantly, amazing regen during mapping. Its easy to stack over 10% ES regen/s with this node alone. Downside is, doesn't work as great vs bosses where there aren't many trash mobs to kill.
Void Beacon: Speaking of bosses, this node will help you out against them the most, reducing their chaos resistance. Also works great against any trash, as the radius covers almost the whole screen.


Major God Power:
The Brine King. Being a CI build, stuns and freezes can be deadly, this pantheon power does help a lot vs both. Very worth upgrading.
Minor God Power:
Yugul. We still deal a fair amount of elemental damage, and last thing you want is to kill yourself on a reflect rare. Even with majority of our damage being chaos, elemental damage that we take being partially converted to chaos, and Yugul power, we still need to be careful about reflect monsters as we do not have instant leech.

Bandits:
Alira. Greatly helps with resistances and also adds some very nice crit multi.

Example 37 points tree
Your first leveling steps might differ depending on skill chosen, for example with Blade Vortex you might want to take Blast Radius sonner. Dex/Str nodes are taken since you most likely will need them for gem level requirements.
Example 60 points tree
Not much to comment here, just take ES/damage nodes depending on your needs. Also, if you still haven't, do your first lab and get Wicked Ward.
With a bit of a twinked gear, you can spec into CI as soon as level 50-55 or so. For example, with Doedre's Scorn (level 39), Ascent from Flesh (44), Rainbowstride (53), 2x Call of the Brotherhood, 170+ES chest (like Zahndethus', level 37, or a rare), +55ES rare gloves and +20ES amulet you can reach 3.5k ES easily at level 54. Add Xirgil's Crank (level 28) for 3900 ES.

Example 84 points tree
You should take CI and Zealot's Oath at the same time, so that your life regen is transferred fully into ES.
Of course, skip staff nodes if you don't use a staff yet, don't unlock jewels if you don't have anything interesting to socket in them etc. Use your head when spending points, not every advice/point is going to apply to your character.

Example 105 points tree
This is more or less what you want in the end game. You can grab more damage nodes instead of some ES nodes, or fill all the nodes around Foresight for more defense. Depending on the variation/gear, you might need to take some other Dex/Str nodes, or Blast Radius if your skill is area based. Growth and Decay is also a good defensive option for +2% regen.

Blade Vortex: 426k dps at 10 blades, 1.117k dps at 20 blades with Concentrated Effect. 271k dps at 10 blades, 713k dps at 20 blades with Increased Area of Effect.
BV + Physical to Lightning + Spell Echo + Increased Area/Concentrated Effect + Elemental Focus + Cold to Fire or Added Lightning
You will need Enlighten in your aura setup to cast this spell without other mana reservation bonuses, and possibly a mana flask if you want to have any hope of reaching anything above 8-10 stacks without leeching mana at the time of casting.
Dexterity might be a problem if you want this to be your main skill.
Passive tree note: Take Blast Radius and Potency of Will notables on the tree. You might need to sacrifice Staff nodes next to Templar to get them.

Ethereal Knives: 340k dps (277k CwC)
EK + Physical to Lightning + Spell Echo + Elemental Focus + Faster Casting + Cold to Fire
You will need Enlighten in your aura setup to cast this spell at all without other mana reservation bonuses.
You can bypass mana problems by using Blight + Cast When Channeling + EK + Physical to Lightning + Elemental Focus + Cold to Fire or Added Lightning. However, you will deal 25% less dps overall, which still might be a fair trade.
Dexterity might be a problem if you want this to be your main skill.

CwC Arc: 298k dps, more dps with CwC then selfcast.
Blight + Cast When Channeling + Arc + Elemental Focus + Cold to Fire + Controlled Destruction.

CwC Spark: 309k dps, only slightly more dps with selfcast, meaning CwC>self.
Blight + Cast When Channeling + Spark + Elemental Focus + Cold to Fire + Controlled Destruction.

Glacial Cascade: 338k (216k without Conc), more dps with CwC then selfcast.
Blight + Cast when Channeling + Glacial Cascade + Physical to Lightning + Concentrated Effect/Increased AoE + Elemental Focus

Auras + Curses:
- Discipline
- Blasphemy + Warlords Mark
- Herald of Thunder

Buffs and debuffs:
- Stone Golem for defense, Flame Golem for offense, and Lightning Golem for self-cast variations. Choose depending on preference/primary gem. Golems work best in a CwDT setup.
- Phase Run - also in CwDT setup, speeds up map clear and helps you get out of sticky situations.
- Vaal Lightning Trap is great vs all bosses, if you don't forget to use it.

Totem:
- Wither + Spell Totem + Faster Casting + Increased Duration. No other choice here.

Movement + Arcane Surge:
- Flame Dash + Faster Casting + Arcane Surge + Increased Duration. Keep Surge at such level so that it procs with a single Flame Dash skill usage.
I might also test Leap Slam for movement skill and Arcane Surge proc.

https://pastebin.com/FbSeTVf0
Level 90, added some gem combinations for different skills.
Note that you need to spec into Blast Radius and Potency of Will, while taking out some other nodes if you want to get more realistic Blade Vortex dps + you will need Enlighten 3-4 with your auras.