Level 93 Crit Lightning Strike Slayer^3.25

Notes

Lvling PoB: https://pobb.in/T7uqGiDzeiiP (swap to this pob after you complete campaign, check the notes)

When do I swap to crit? - When you're around lvl 80-85, have lycosidae and a decent crit claw. There is no rush to crit swap, the non-crit setup is pretty good with rebuke of the vaal.
(keep in mind you want 20 quality on your assassins mark or you wont generate power charges).

Upgrade order: 2 taming > lethal pride > yoke of suffering > ralakesh > hh > nimis > progenesis (can get it before nimis if you want)

Optional flask: Can either use divine flask flask or amethyst flask. If you opt for vaal pact then you can no longer use a life flask. Replace amethyst flask with progen once you acquire it.

Defenses needed for T17: 100% spell suppression, ralakesh, ailment immunity, 70% crit reduction(from chest), fortify(chest implicit) and 7 frenzy charges(+1 from ascendancy and 3 from skill tree)
ideally you want enoug dps to kill the fortress boss within 5-7 seconds on a map with no tank mods.

Hybrid gear or evasion gear? - Hybrid arm/eva gear is The best but it's usually more expensive, this is why i opt for evasion gear early on to get cheaper pieces (if hybrid is the same price then get hybrid)

"Where do you get rage?" - Either implicit on gloves or +1 rage on melee hit on your timeless jewel. Timeless jewel guide: https://www.youtube.com/watch?v=_kYy-s_B-ng
Besides +1 rage on melee hit you would also want as many "5% chance to deal double damage" on your lethal pride.

Take lucky spell suppression on the spell suppression master if your spell suppress isn't cap, 60-70% with lucky is good enough for early progression.

Daggers are also usable, although require 1 extra point (you just drop the claw wheel for the dagger wheel right above it).

Can takeout Pierce on tree when you get +1 pierce craft on helmet and +1 pierce on gloves.

To be ailment immune with ancestral vision you need 110% spell suppression, 25% chance to avoid ailments on chest and the "thick skin" life wheel on the skill tree.

Ascendancy order: Bane of Legends > Headsman > Brutal Fervour > Masterful Form(try to complete uber lab asap, massive for defense).

+1 frenzy implicit rings are better then tamings but can be quite expensive
You'll also eventually want a +1 frenzy implicit shield (also expensive).

What about LS of arcing?: LS of arcing is only useable once you acquire 2 clusters with fan of blades, but if you're not doing high dense maps then it's not rally worth it as your single target decreases.

--------!!!!important!!!!------
It's extremely important to freeze in this build or you wont have high damage. If you have trouble freezing then before acquiring nimis you can try using awakened added cold over return projectiles.
Avoid running ailment maps as you wont be able to freeze.
Before swapping to the heatshiver setup you're going want to craft the cold claw and have abyss jewels with flat cold, heatshiver wont work unless you freeze enemies.

Get resist wherever you can, the rare gear has open suffixes to help fill out your resist. It's quite easy to get resist cap with double taming and yoke of suffering, you might struggle with chaos res.

Your automation/assassin's mark can be lower lvl if you're struggling with int. Ideally you do want them at lvl 20.

Preferable you want every jewel with double flat cold damage (to attacks and with claws) it's more effective then anyother flat because of heatshiver.

Reminder that "quickstep" on the passive tree is 2 skill points for 13% spell suppression if you ever need it.

----Crafting Guide-----  
Video: https://www.youtube.com/watch?v=yjDq9DQ13D8

Everything here can be recomb for a lot cheaper, it's a bit more advance but quite easy to do once you learn recombs.

Cheap Claw: (want a 1.5 attack speed base or better, Imperial/noble are the best bases)
1) Buy a fractured cold damage, attack speed or crit chance base. 
2) If it's fractured cold damage, then spam zeal essence until it rolls crit chance - If it's fractured attack speed or crit, then spam hatred essence until you hit atk speed or crit. 
3) At this point you can just craft "hit's cannot be evaded" and be done. If you have open prefix/exalt, feel free to exalt slam. (if you have fractured cold damage with an open suffix, you can also lock suffix and reforge crit for multi).
With 2 open prefix and 1 open suffix, you could also multimod to get ele pen/hit's cannot be evaded.

Expensive Claw:
1) Buy a fractured cold damage claw
2) Spam zeal essence until crit chance or crit multi
3) Need 1 empty suffix, might have to annul here. Craft "suffixes cannot be changed" and reforge crit. This will guarentee crit chance or crit multi.
You now need 2 empty prefix, if you need to clean your prefix then do "suffixes cannot be changed" and scour orb. Since your cold damage is fractured, it cant be removed.
4) Craft "suffixes cannot be changed" and vailed orb. Before unveiling, make sure you block %phys damage.
5) unveil pen and craft hit's cannot be evaded
(do note that t1 lightning or t1 fire damage is equal in dps to pen, so if you're doing recombs this would be cheaper then veiled orbs.)

Body armor with crit reduction
1) Buy a fractured spell suppression base (ele resist base could also works, but will make the essence spam a lot more expensive)
2) Spam essence of horror until you have t2 or better resist.
3) use 1 exarch ichor to make it the dominant implicit
4) Use a combination of eldritch chaos, eldritch annuls and eldritch exalted orbs until you hit t2 or better life
(If you're doing the annul/exalted orb method, then make sure you craft flat evasion before every exalt)
Example. Craft flat evasion > Exalt orb (if miss) > take off the crafted mod > eldritch annul > repeat
Both methods are valid, it all just depends on market price.
Depending on prices you can also use wild bristle matron to force on "suffixes cannot be changed" and then reforge life with harvest.

Gloves: If no temple mod then just buy these instead of crafting. Here is how you craft the high end versions.
1) Buy a "increased damage against chilled enemies" either fracture or you have to fracture yourself. - This mod isn't needed so if you want cheaper gloves, just buy fractured res or spell suppression
2) Spam zeal essence until desired suffix (resist or spell suppression)
3) use exarch ichor to make it the dominant implicit
4) Use a combination of eldritch chaos, eldritch annuls and eldritch exalted orbs until you hit t2 or better life
Example. Craft flat evasion > Exalt orb (if miss) > take off the crafted mod > eldritch annul > repeat
Depending on prices you can also use wild bristle matron to force on "suffixes cannot be changed" and then reforge life with harvest.

Shield: Get a fractured spell suppress base
1) spam spite essence until desired suffix (resist or attack speed)
2) Use wild bristle matron in bestiary to force on "suffixes cannot be changed" and reforge life with harvest, repeat until t2 or t1 life. 
This does have a chance to fill your prefixes, in which case you'll have to annul. This can brick your shield in which case you'll have to start over with step #1