Hey there.

Something happened and I've decided to try different weapons in my arsenal using Heavy Attacks. Most of them weren't any good but there was exceptions too. [Hate] is one of them.

Why?

Because of this:

600% of Heavy Attack's damage and guaranted Slash proc.

Well, what should we do? Here comes the explanation:

Sacrificial Steel - increases Crit Chance by a lot
Pressure Point - increases basic damage
Amalgam Organ Shatter - increases Crit Damage and decreases Wind Up animation of Heavy Attack
Killing Blow - increases Heavy Attack damage and decreases Wind Up animation of Heavy Attack
Corrupt Charge - makes starter Combo Multiplier 2x
Blood Rush - increases Crit Chance by 32.8%
Gladiator Might - increases Crit damage by 60% and Crit Chance by 10%

Some mechanics:
Each Combo Count multiplies the damage. So 2x combo = 2x damage, 3x combo = 3x damage and so on
Attack Speed decreases time of animation that plays after Heavy Attack. I don't use it because of low basic value of 0.917 while Wind Up speed decreases time of animation before Heavy Attack
Critical Hits are multipliyng damage of Slash proc
Faction Mods greatly affect DoT. You can look for full explanation at wiki or builds of the user named The-Simulacrum-Warriors
Slash DoT bypasses armor dealing True damage type directly to HP
Physical and Elemental Damage mods like [Rending Strike] or [Molten Impact] do not affect DoT

Performance

Here I have to confess: I have MR15 and because of that tests were made at 105 lvl Corrupted Heavy Gunners.
At this level they have 74 696,32 Cloned Flesh HP and 6 681,71 Ferrite Armor providing them 95,7% of damage resistance (which won't bother us because we'll utilize Slash proc's True damage). To kill that mob, you'll have to make just one or two Heavy Attacks (one for crit, two for non-crit). Do that and move further because mob will die after 3-5 ticks of Slash. "It's too much time" you might say. But remember that Heavy Attack of scythe knocks down the enemy. Also, you shouldn't wait for enemy's death. Slash will do everything for you while you can move further and make more enemies bleed to their death. Looks cool.
Until you meet an Eximus unit. Their new type of shields mostly ignore that damage and you'll have to switch your weapon there.

Possible additions and replacements (will require Forma):

Fury/Quickening - decrease time of animation that plays after Heavy Attack
Gladiator Vice - same as Fury but with little additional bonus to Crit Chance
Reach/Spring-Loaded Blade - makes more enemies bleed (thanks to ok Follow Through of 0.6)
Reflex Coil - entry to Hybrid build (utilizes stacking Combo Count and using it for Heavy Attack). Saves you Combo Count for next attacks
Relentless Combination - entry to Hybrid build. Almost each slash tick will return you a Combo Count
Smite (faction) mods - check "Mechanics" section

"Conclusion"

This build neither the best [Hate] build nor the best Heavy Attack build. Hybrid build may be better but it will require polarizing while this build is low-cost (which is one of the main reasons why it's even viable). It's just fun, cheap and decent build for those who haven't access to rare mods at the moment. Anyway, you are free to play with Mod Ranks and Mods themselves, just stick to the concept given. Also, I'll be glad to see your suggestions and to ask your questions.

Happy hunting!