What is a Stat Stick?
Stat Sticks are weapons that are used as vessels for modding pseudo-exalted weapons. Each pseudo-exalt is modded differently, and this build is about Khora's pseudo-exalt, Whipclaw.

Which Mods Affect Whipclaw?
As per the wiki:
~Rivens
~Augments
~Status Chance
~Melee Damage
~Combo Duration
~Elemental Damage
~Physical Damage (IPS)
~Critical Chance/Damage
~[Blood Rush], [Weeping Wounds] and the Gladiator set bonus
*Augment and Riven stats that conflict with the list of working mods will not apply.

Other Factors That Contribute To Damage
~Incarnon evolution perks do affect Whipclaw. For example, [Innodem]'s Swooping Lunge will give extra base damage.
~Zaw Arcanes do not affect Whipclaw's damage.
~Headshots deal double damage.
~Modded Ability Strength will increase Whipclaw's base damage.
~Ensnare and Strangledome have unique ability synergy with Whipclaw. Ensnared enemies take double damage. Enemies trapped by Strangledome will all be hit by a single cast of Whipclaw. The original target takes 100% of the damage and the other enemies take 50%.

Modding The Stat Stick
You can mod for either raw damage or proccing Slash. This guide covers the Slash build.

Our priorities are proccing Slash and buffing the damage of the Slash tick. To proc Slash, we're going to need ≥100% Status Chance and a good Slash IPS weighting. The optimal way to do this is to use Weeping Wounds and a Riven with +Slash and -100% Impact or Puncture. To consistently get -100% you should use a weapon that has a 1.25 Riven disposition or higher. In the event that you don't have a Riven with those stats, [Buzz Kill] will have to be slotted over [Spoiled Strike]. If you just straight up don't have a Riven, [Buzz Kill] has free slot and you don't need to replace anything.

What buffs the damage of a Slash tick? Faction Damage, critical stats and base damage. Faction Damage doesn't apply to Whipclaw, so we can go all in on critical and base damage stats. The priority list is Critical Damage > Melee Damage > Critical Chance. The caveat being you need enough Critical Chance to actually consistently get a critical hit. The only options for Critical Damage are [Organ Shatter] and [Gladiator Might], Melee Damage comes from [Primed Pressure Point] and our Critical Chance is provided by Blood Rush and the Gladiator set bonus.

If you've been keeping track, we've used 6/8 mod slots so far (PPP, BR, WW, OR, GM, BK/Riven). The question now is what goes into the last two slots? There are 4 options. We can only use 2 (or 1 if you have a sub-optimal Riven). Those are [Sacrificial Steel], [Gladiator Rush], [Blade Of Truth] and [Spoiled Strike]. Simply put, [Gladiator Rush] is the best and [Sacrificial Steel] is the worst.
*[Spoiled Strike] is equivalent to the Syndicate Augments if you are using one of those weapons. In this case, we have [Blade Of Truth] on the [Jaw Sword].

Critical Damage > Critical Chance?
Technically, a higher critical tier does more damage than adding extra Critical/Melee Damage. However, if you cannot consistently get Whipclaw to hit said critical tier, you have lower damage overall. This means that, mathematically, unless you can guarantee a red crit, modding for Melee Damage and Critical Damage to buff an orange crit will be better for your build. Now you might be thinking, "ok so that means, I slot [Spoiled Strike] and [Blade Of Truth]". In theory yes, but remember the consistency of crits? [Gladiator Rush] allows for a substantially more consistent orange crit rate, which is more valuable than [Spoiled Strike]'s +100% Melee Damage. This applies even if you have Gladiator mods installed on your Warframe.

Riven Stats
For the optimal Riven, there are 2 options. You can either use a CDM+MD+Slash with -Impact/Puncture, or MD+CD with a negative (preferably Impact/Puncture). Obviously any decent Riven roll will provide a massive damage boost to Whipclaw, but those are the optimal stats. In terms of negatives, there are quite a few options that are acceptable. They are as follows:

Acceptable Riven Negatives:
~Impact
~Puncture
~Faction
~Status Duration
~CC on Slide
~Range
~Attack Speed
~Finisher Damage
~Heavy Attack Efficiency

What's The Best Weapon For A Stat Stick?
While Whipclaw does good damage on its own, Rivens are what really push it into S-tier damage potential. This means in general, any low disposition melee will work. However, as of patch 33.0, the Incarnon [Skana] (not the [Prisma Skana]) is the best due to a bug where the evolution perks provide increases to Whipclaw's base stats. When that gets patched, most likely the [Ceramic Dagger] Incarnon if you have a Riven, or the [Innodem] if you don't have a Riven would be the best. However, Whipclaw is so powerful that even without a Riven or Incarnon evolution perks, you will be able to do Steel Path very easily, so just use whatever if you don't want to invest a lot of time and/or money.

Stat Stick Calculator