What Arcanes must use for primary weapon?

[Sugar Show]

what are the best arcanes for add damage to riffles?
I run critic build.

[Fake]

Use whichever you want.
They aren't needed/required for any content that's currently in Warframe.

[[Meyo]Frakura]

Arcane Merciless is pretty good and Im pretty sure is common on most build, granted you are killing things fast enough to stack and make the buff last. The other arcane is based on preferences.

[Midas]

-Arcane Merciless is good if your primary can kill quickly already and/or is a decent AoE weapon.
-If you need to actually aim it to get kills, Arcane Deadeye is what you want, since it's going to rack up faster and last longer (and buff headshot damage on top of that)
-If your melee weapon is still your best damage dealer, use Arcane Dexterity. (and use it on your secondary too, since the combo duration stacks, and melee kills will buff both weapons)

The actual weapon build only matters for Deadeye, which requires actual headshot kills, not status kills. Status kills from the primary will trigger merciless, but not deadeye.

[Twisty]

I prefer deadeye on rifles, it's pretty easy to land a headshot kill even if you aren't actually trying for them.
Most of the time you'll have the buff up.
Merciless is great for shotguns and rifles that can kill quick like the Fulmin, although deadeye works just as well.

For melee frames or if you melee is stronger use dexterity.

[:3]

pretty much always deadhead