Non-crit Raw Damage Viral Heat build enough to kill pretty much all content very quickly and even scales in steel path without armor strip up to level 1000 thanks to the multiplier from Devouring Attrition.

Viral Slash alternative (scales higher without armor strip against Grineer/Corrupted): https://overframe.gg/build/315630/

Evolutions

• Evolution I - Incarnon form - 12 headshots (less with multishot) lets you switch to Incarnon mode after alt-fire which has about 408 rounds

• Evolution II - Void's Guidance - +50% Accuracy and -50% Recoil. The combination of this perk with Primary Deadhead gives -100% recoil. If you run stabilizer in exilus as well as primary deadhead, you can run Rapid Wrath (+20% fire rate) instead.

• Evolution III - Ready Retaliation - +100% reload speed for 6s when reload from empty. This actually also affects the transformation time, cutting it down from 3.4s to approx 1.7s if you manage to reload from empty.

• Evolution IV - Elemental Excess - +20% status chance, -10% critical chance. This drops the final crit chance to 10% to synergize with Devouring Attrition and makes the final status chance approximately 70%.

• Evolution V - Devouring Attrition - 50% chance to deal 2000% damage on non-critical hits. This 2000% multiplier is currently a separate multiplier to base damage mods such as serration, deadhead, galvanized aptitude

Mod Explanations

• Galvanized Chamber - +230% multishot at max stacks

• Galvanized Aptitude - +80% dmg per status, so +320% with slash, radiation, viral and heat, or even more if you use an external primer.

• Primed Shred - needed for fire rate and punchthrough

• Primed Bane of Grineer - additional 1.55x multiplier. If you don't like bane you can replace for Amalgam Serration or Vile Acceleration

• Viral - A single viral status proc doubles the damage of all subsequent damage, to a max of 4.25x at 10 stacks of viral. Viral also has a damage bonus against Cloned Flesh and Flesh possessed by Grineer and Corpus. [Rime Rounds] is a cheaper option over Primed Cryo Rounds, but you can use Primed Cryo Rounds for slightly more upfront damage at the cost of status if you add more forma.

• Hellfire - Adds heat damage and procs. Heat procs strip up to 50% armor and can stack indefinitely to do damage, and have bonuses against Cloned flesh which is possessed by all Grineer units as well as

• Thermite Rounds - This is the FLEXIBLE slot. I have placed [Thermite Rounds] here to further increase the heat weighting (so heat procs more often than viral and each heat proc does more damage per tick) while also giving more status chance (final status of 92% after elemental excess).

Flexible Options
If you want to invest more forma, you can swap Thermite Rounds or any other mod you don't own for any of the following flexible options:

1. Vile Acceleration - stack more fire rate with primed shred for highest sustained DPS (i.e. if you hold down fire and spam shots)
2. Amalgam Serration - additive +dmg to aptitude and deadhead but also gives bonus sprint speed
3. Primed Fast Hands - cuts a further 1 second from the transformation time (3.4s to 2.4s without Ready Retaliation active, or down to 1.5s when stacked with Ready Retaliation) and improves feel of non-incarnon mode.
4. Riven - look for +ms, +dmg, +fire rate, +tox, +reload speed wit negative crit chance.
5. Vigilante Armaments - slight boost to multishot

Building for Other Factions

For Corpus: Swap [Rime Rounds], [Thermite Rounds] and [Hellfire] for [Infected Clip], [Amalgam Serration] and Vile Accelation to make pure toxin to bypass shields, and swap bane mod.

For Infested: Swap Rime Rounds for High Voltage or Stormbringer to make corrosive heat, and swap bane mod.

For Thrax/Acolyte: Make raw corrosive by swapping [Malignant Force] for [Infected Clip], [Rime Rounds] for [Stormbringer] or [Jolt] and drop Bane mod for [Amalgam Serration]. Consider dropping [Primed Shred] and [Hellfire] for [Vile Acceleration] and Vigilante Armaments.

Xata's Whisper Synergy and Calculations

With all mods and multipliers at 4 status and max stacks, every non-critical single-projectile hit should do:
140 x (1+1.65+3.2+3.6) x (1+0.6+1.65 +0.9) x (1+0.55) x (1+20) = 178K damage

Combine with [Xata]'s Whisper for two insane effects:
1. Devouring Attritions 21x multiplier actually applies a second time to the void damage instance, which itself is weapon damage x [Xata]'s % multiplier x ability strength. This means you are actually getting a final multiplier of damage x 21 x 21 = 441x, or approximately 178,714*21=3,752,994 aka 3.7 million raw damage per shot before applying [Xata]'s multiplier and faction mods which apply a second time (double dip).

If you get a HEADSHOT with [Xata]'s, the void damage will actually double dip both deadhead (1.3x) and the headshot multiplier (2x) as well as dipping faction mod again (1.55x) giving a final headshot damage of approximately 3,752,9941.31.322*1.55=39 million damage.

2. [Xata]'s void bubbles seem to spin and ricochet [Phenmor]'s projectiles in a 360 degree range allowing you to hit an kill enemies adjacent to the initial target as shown in these videos:

Here is a video demonstration of the synergies with [Xata]'s Whisper:

.