Level 83 Crit Flicker Strike Slayer^3.25

Notes

--- Foreword ---

This is a Flicker Strike levelling guide that utilizes Sunder to level until you are able to flicker.

If you are new to Flicker Strike or Path of Exile in general, then hopefully this guide will be able to assist you in levelling.
If you have any questions please, there is a discord for MAGEFIST (https://discord.gg/EqrMATBnZp), you can create a post on pob-links for help, or just ask in a channel. 
The levelling guide was made by A Guy, so you can ping him if you want some help.

And as with any other melee levelling please follow this EXTREMELY IMPORTANT RULE OF THUMB: Upgrade your weapon
Once an act should be good enough but if you ever feel your DPS is falling behind, you probably haven't gotten a new weapon in a while.

--- Act 1 ---

We are starting with Frost Blades early, this skill is very strong early but will be replaced with Sunder, which is just broken.
After you kill Hillock go over to the vendor and grab Frost Blades, you can look within Tarkleigh's vendor window for a 3-link, a 2g1r, you can paste this regex:
g-g-r|g-r-g|r-g-g
and all correct items will highlight. There may be none. This is not a required thing, but it will help you possibly find better gear.
Try to also look out for a Ruthless skill gem in the gem vendor and purchase that, keep it socketed in whatever open sockets you have.
Although I haven't put it in the gems section, you can equip Steelskin and press it every once in a while to make yourself a bit tankier.

You should always try to get the highest pDPS axe you can, basically just look for whatever has the biggest physical damage on the top of the weapon. Which must be a Two-handed Axe

--- Act 2 ---

In Act 2 we pick up our mana leech node, which makes levelling extremely comfortable and smooth. In terms of gems we swap over to Sunder, supported by Ruthless and Close Combat if you have the 3-link.
As you progress into the act you get the auras, Blood and Sand and Herald of Ash which are extremely powerful gems for damage and clear.
You also get Blood Rage which you can use at the beginning of areas to get you Frenzy Charges, speeding you up a lot.

--- Act 3 ---

We add a few auras here, Determination and War Banner. You can place the banner on bosses if you feel like you don't have enough DPS.
You also should only press Vulnerability on bosses, as you already have the clear damage.
Finally, we get our lab towards the end of the acts, where we allocate Impact for some more damage and accuracy.
Speaking of Accuracy Rating, try to find some on bits of your gear, it helps your damage out quite a bit and it is undervalued in my opinion.

--- Act 4 ---

It is about this time where you should also check to make sure you are levelling Flicker Strike and other related gems in an off-hand weapon in order to make sure that the transition later is smoother.
You also can socket Berserk which you can use when you reach maximum Rage on a boss for a bit more damage!

--- Act 5 & 6 ---

Not much is going on here, you should just be able to keep on rolling the campaign, if you are ever feeling weak, it is all because of your weapon, find one with a higher physical damage roll.
Keep upgrading it!

--- Act 7 ---

Here is where you get your second ascendancy, Brutal Fervour, which helps you leech better. 
If you are a risk-taker and willing to ruin your league start a little, you can start Flicker Strike even this early, if you can afford Terminus Est that is, look to later parts of this guide for more tips.

--- Act 8 & 9 ---

Not much else to say about these acts either, just keep levelling!

--- Act 10 ---

Here it is possible to swap to Flicker Strike if you can afford Terminus Est, you HAVE to allocate Tribal Fury in order to make Flicker Strike work!
You also can get 3rd lab, Bane of Legends boosting your single-target unique damage.

--- White Maps ---

All the respecc'ing with swapping to Flicker Strike should be able to be from your quest rewards, but you can of course use Gold as well with Faustus.
There are a lot of things to make sure if doing when using Flicker Strike, make sure Tribal Fury is allocated, make sure you are using Multistrike.
Using Assassin's Mark is very powerful to ensure the generation of Power Charges, which is monumental to your critical strike chance and therefore, Frenzy sustain.
If you really need it, you can swap out Determination for Purity of Elements, if you really need resistances, it isn't fully recommended though.

--- Yellow Maps ---

Now that you have gotten the final ascendancy point, Masterful Form, you must press Enduring Cry to sustain your endurance charges, which is clunky, this is what you have to do until you reach Replica Farrul's Fur.
There are a few other uniques you can get around this time to increase DPS, if they aren't too expensive at the time.
Anointing Fervour is good for DPS but not too required, so you don't need to focus a lot of your money onto it.

--- Red Maps ---

Reaching red maps has you put even more crit onto the build, so make sure to use your diamond flask. Higher end investments of this build will be going into Replica cFarrul's Fur and higher DPS weapons.

!!! FAQ !!!

--- Ascendancy ---

Impact -> Brutal Fervour -> Bane of Legends -> Masterful Form

--- Frenzy Charge Generation ---

Frenzy charge generation in this build is very straight forward. We use Terminus Est which grants us a Frenzy Charge on critical strike. Since we attack 3 times per strike, due to Multistrike, we really only need about 30% critical strike chance.
That is the bare minimum for sustain on bosses, however you of course want lots more for better daamge and sustain in general.
There is also a second time in which you need sustain, on packs, if you can sustain on bosses then you can sustain on packs easily. However, if you want a second option, you can use Blood Rage, this can theoretically let you Flicker Strike
before even getting Terminus Est but that is not recommended as you need to swap out on bosses.

--- Issues with Flicker Strike ---

Flicker Strike of course is not the simplest gem to use and lots of people have issues with it to begin with. So to find what the issue is, when flicking, look at your Frenzy Charges, if they run out, consult the previous section. If it simply feels very clunky
then you may not have Tribal Fury and its mastery allocated, or you might not have Multistrike linked. You also want to keep the "Always attack without moving" box checked in your Flicker Strike.
If you checked all of these things and still have clunkiness, then you can ask on the Discord for more personalized help.

--- Bandit & Pantheon ---

Kill Alira league start, then later when you get more money and can get better gear, swap to killing all bandits.
For pantheon you most likely want Brine King (Major) Tukohama (Minor). This gives freeze immunity (if you unlock the power with a divine vessel), and more physical damage reduction when stationary, which we always are with Flicker Strike.