Chair's 3.10 Arc Elementalist

The build is somewhat expensive with the most expensive item being 6 link Shavronne's wrappings.

List of costs for the build at the time:
Hypnotic Eye jewel - 1C
Stygian Vise - 2C
Mark of the shaper - 8C
Doedres Damning - 1c
Crown of the inward eye - 1c
Void Battery - 20c
Shavronne's Wrappings - 3ex

For rare items this is the price I got mine for but depending on your budget the prices can be much less or much more.
Rare gloves - 18c
Rare boots - 5c

This build will probably not be able to get through 100% of the content such as endgame bosses, but it is one of the most fun builds I've played.

Pros
Crazy clear speed - Can 1 shot entire screens of enemies
Great for clearing deliriums
Great for delving
Lots of fun to play (your basically like Zeus with this build)

Cons
Can be squishy - this is only ever a problem on bosses because all regular enemies are dead before they can get close
Bossing is pretty terrible - high tier map bosses can one shot you pretty commonly, and because of arc's low attack speed especially with spell echo support you are stuck standing still for a second to attack.

The playstyle for fighting common enemies is pretty straightforward, fire arc and everything dies.
For enemies that won't usually be one shot such as blue/yellow enemies or magic resistance enemies on high tier maps you will want to fire the ball lightning which curses enemies with conductivity and assassin's mark. For boss fights you will also have to be dodging a lot due to the build being somewhat squishy.

Void Battery Wand
Links - Flame dash

Rare Energy Base Shield
Links - Blood magic support and wrath

Crown of the inward eye
Links - Cast when damage taken support and steelskin

Shavronne's wrappings
Links - Arc, elemental focus support, inspiration support, spell echo support, energy leech support, and arcane surge support

Rare energy base gloves
Links - Curse on hit support, ball lightning, assassin's mark, and conductivity.

Rare energy base boots
Links - Herald of thunder, zealotry, enlighten support, and discipline

Stygian Vise
Jewel - Rare hypnotic eye jewel with critical chance or critical multiplier.

Doedre's damning

Mark of the shaper

Rare amulet
I used a paua amulet to increase mana regen but almost any rare amulet can be used instead of it.


What to look for on rare gear
Top priority - Energy Shield and Resistances

Also good to have - Added crit chance or multiplier, increased damage for spell/elemental/lightning, and + to the level of socketed gems.

Flasks used - 2 Diamond flasks, 1 Sulfur flask, and 2 Mana flasks. The only flask that is required is the diamond flask.

Passive Tree
www.poeurl.com/cRbt

PoB
https://pastebin.com/At0FMrkd

Configuration - It assumes you will always have a diamond flask in use with how quickly flask charges are generated which is why crit chance is lucky is on. Enemy is shocked is enabled because our attacks have a 90% to shock enemies. Feel free to mess around with configuration to see how different things affect the build. For example with energy leeching enabled our DPS will go up significantly.

Elementalist
1. Pendulum of Destruction - Pretty unreliable buff and not the best ascendancy but it leads to an ascendancy that is very powerful.
2. Mastermind of Discord - Powerful skill that makes our heralds a lot stronger and cost less mana to reserve them.
3. Paragon of Calamity - makes the build slightly tankier and if going against lightning enemies will increase DPS.
4. Liege of the Primordial - increases strength of golems if you decide to use an ice golem for the bonuses to crits.

Alira can be viable because the build only uses 120/123 passive points and her crit multiplier + resistance buffs are very helpful but I chose to go with 2 passive points since most people will not get as far as 99.

Leveling with arc is much smoother than most builds because of how easy it is to stay on target level while rushing through acts. It is also very helpful that arc becomes available early on.
Some good uniques for leveling are the Tabula Rasa, the Axiom Perpetuum, and the Goldrim.

After the acts if you cannot afford Shavronne's Wrappings 6 link you can either buy a 6 link rare energy shield body armor or buy a 5 link Shavronne. If you choose to buy a 5 link, taking off energy leech support should have the smallest affect on our DPS because we are not leeching very often. If you choose to buy a rare chestplate you should take Chaos Inoculation on the passive tree so you don't get 1 shot by chaos damage and once you can afford Shavronne, refund CI. You will want to get Shavronne's wrappings quickly because blood magic does not work with CI and wrath is a very important aura for us.

Thanks for taking the time and reading my build!
If you decide to try out my build I would like to know how much you enjoyed it and if there is any part of it that can be improved.
Have fun with my build and good luck exile!