Level 96 Hybrid Corrupting Fever Elementalist^3.27

Notes

Starting: This build is already t17 and uber viable if you know what you are doing but it is a little on the squishy side thanks to the unique chest we have to have for damage.  If you are bossing I suggest you switch to the vaal souls runegraft which will help with your vaal reap uptime.

Step 1: First step is to try to get additional tankiness without sacrificing damage. We will craft a shield .  You get i86 titanium bases and you alt craft t1 energy shield % , t1 flat energy shield , t1 block chance and recombinate them. Remember to craft a low mod to lower dust cost.  
This method is called 2 + 2 = 3 where u can any of the 2 mods you want x 2 and recombinate them for 3 mods.  This will take you several tries.  I did it last night and took me about an hour of alts and 1 mil dust.   After that if you have 2 open suffixes you can apply a shapers exalted orb if not you have to use prefixes cannot change and scour.
If you do not get ES on block you have to do prefixes cannot change and reforge defense til you get it, there is about a 10% chance you hit full suffixes, if this happens you have to blind annul gl.  If you are poor you can skip the whole shaper section entirely til later as it isnt that important because your Energy shield is low(eventually you'll have to do it).

You are going to lose damage here so you will buy empower 4 and try to upgrade a few jewels so your damage remains roughly the same. The shield is rougly 22 divs to make, Jewels few divs empower 7.  31 to complete this step if you have normal RNG
On your tree you will remove one point from bottom left mastery and hopefully youve leveled by now to 97 and you can take a jewel slot for additional damage

 Step 2: In this step we will be crafting an amulet to give us big damage but we will lose some max res because of the flask setup.  We cannot use 4 flasks til a rare chest so this is the bandaid solution.  Get a focused amulet roughly around 30 divs at the moment and use Harvest reforege life til t1 life then annul the amulet til the mod is alone.
Then use Cannot roll attack mods and Harvest Augment phys.  This is a 50/50 to win.  If you end up with +2 phys and 250+ life craft non damaging ailments and catalyst life on you amulet.  On the flask section we change to bismuth flask and use a Fluid motion for dex and changing some of our crafts on gear.  On the 
tree you will remove Juggernaut and Endurance(if you didnt level again) and apply them to Discord Artisan for more dex and damage.    
This whole step will cost you 45-50 divs if your RNG is okay.

Step 3: This setup you will be grafting your wand for a Big dps upgrade.  Fractured 38 Physical damage overtime multiplier on a cast speed base wand. 
Use jagged metallic shuddering corroded fossil to get +1 to all spell gems.  From that point you want to get your wand to +1 spell gems 2 empty prefix,  the fractured mod and any suffix.   If youve annul'd off the random suffix you want to craft 3 crafted mods beefore you want to use cannot roll attack mods and use Augment physical. 
Craft 3 crafted mods, cast speed and minion damage.  If you leveled take your endurance charge back on your tree.  You will also recraft gloves here and the whole point of this step to improve your speed you will switch to frostblink soon.
Get qualitied Warlock Gloves and Use insanity essence and try to fracture them.  Then use Dense fossils til desired energy shield.  Use eldritch currency on the bottom for Dex. 

Step 4: Megalomanics, they will be expensive. You want to copy them from the trade site into pob to see the positioning on the nodes. Buy the ones that arent in the back so you dont waste points.  If you find ones with 2 good nodes then you can take those too for the sake of simplicity the pob will have 1 pointers. 
We are crafting boots here.  Get fractured %energy shield from the market there are tons for cheap. Spam Spite esssence til any t1 resis with open suffix.  Use suffix cannot change and veiled chaos til suffix veiled try and unveil non damaging ailments.  Repeat this until you are done.  Use wild bristle matron
and reforge life til t1 life and craft Onslaught for now.  You want to do this because we are changing the timeless jewel so you can get frenzy charge on kill for more mapping damage and faster casts its also an easy way to get more dex, if you cannot get one with dex then you have to use a place holder jewel.

Step 5: New chest: Get a high % Twilight regalia and use Corroded and Facted fossil til +1 strength gems and attempt to fracture.   Use dense fossils til high ES and then use prefixes cannot change and veiled chaos to do a suffix.  You are looking for ES regen or good stats.  Now you want to get a Double mod bereks to free up a ring slot
Craft helical Ring.  Use dot multi essence til dex or int, Suffix cannot change veiled orb block and try to unveil frenzy.  Use suffix cannot change aug caster.  craft life.  Get more megalomanics and grab one jewel to fix res.  Double check your gems to make sure you have 21s.   You can also do 3 crafted mods prefixes cannot change on your shield now 
to veil orb for stats so you can free up a suffix to craft for res so you can get more damage from jewels.