This is a red-crit build, which means that it's gonna get you those crispy red-crits as long as you maintain the 12x Combo multiplier.

Mod Reasoning:

[Primed Fury]: Since this is also about the dps, a fast mod would be essential to dealing more strikes efficiently.

Gladiator mods and Blood Rush: These mods are the most essential to this build since they increase crit-chance by a given amount per combo, you can switch [Gladiator Rush] for [Gladiator Vice] if you want more speed.

[Primed Pressure Point]: Just for greater Melee damage (You can use [Gladiator Vice] if you want more crit or [Sacrificial Pressure] to add on to the Steel)

[Sacrificial Steel]: For even more crit chance and to make it a better "sentient slayer".

[Vicious Frost] and Primed fever strike: For that sweet viral and status damage, primed fever strike is replaceable by the other toxin mods.

For Maximum damage, I recommend using [Steel Charge] with [Excalibur Umbra].