First, listen to this song while reading this guide:
https://www.youtube.com/watch?v=N74cnBa_Bmc

Now let's get to the details:

Keratinos' heavy attack is the new spin to win - it starts with a few spins that deal damage in a good radius and finishes with a ground slam. This build is optimized only for the first part of the heavy attack (the spins), and here's how it works.

It also has a unique ability - if you [Reach] max combo counter, you can use an heavy attack to gain extended claws (extended range) for 3 minutes. This build is not optimized for this ability, however it is doable in a crowded room.

https://warframe.fandom.com/wiki/Keratinos

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MODS
• [Amalgam Organ Shatter] and [Killing Blow] provide wind up speed, lowering it to 0.3.
• Berserker allows you to stack speed, which will be granted easily after the first damaging spins.
• Even though this weapon has good range on its own, [Primed Reach] ensures you manage to hit a bunch of enemies, specially while moving.
• [Sacrificial Steel] is the best critical chance mod for heavy builds (+440% or +550% if used with [Sacrificial Pressure])
• I chose [Primed Pressure Point] over [Sacrificial Pressure] to gain more overall damage at the cost of critical chance.
• Condition Overload and Volcanic Edge will provide extra damage (basically Heat + Viral meta).

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MOVEMENT
• There are a few tricks to manage when using this weapon:
• You cannot start a spin from a slide, however you can slide after you start spinning to gain extra movement/speed or close a small distance.
• If you do not cancel the first spin, you will perform the ground slam heavy attack which we do not want - to cancel you can hold BLOCK throughout your attacks and you will only perfrom spinning attacks (blocking can also be used to leap and spin with regular attacks due to Vermillion Storm (block + forward attack combo)).
• You cannot jump immediately after spinning, but you can dodge roll - good for moving around packs and start another spin as an alternative to stance leap.

https://warframe.fandom.com/wiki/Vermillion_Storm

I hope you enjoy this weapon and build as much as I do. Any feedback is welcome as I have not done many builds before and wish to learn more.