Build Objective
[Valkyr Prime] is the warframe with the most base armor in the entire game, so with that in mind, this build aims to give her the maximum stability of armor/strength possible, plus with Eternal War it'll make you a melee killing machine. (Granted you have a good melee weapon)
Requirements
2 Umbral Formas
2 Formas
Aura Forma (Comes in handy, you'll be able to trade for Steel Charge or literally anything else)
ArcaneGuardian (Helps a lot, you get over 90% damage reduction without adaptation) Or ArcaneGrace
Or Both ArcaneFury and ArcaneAvenger for extra crit
How it works?
Go ham, you're practically unkillable without your 4th. If you go Steel Path with a team, suggest for someone to bring an [Oberon] or [Wisp].
4th ability for emergency times only. Have fun.