"Kill them before they can kill you" - That's the entire concept of this build.

TL;DR
Pull out [Exalted Umbra Blade], and spam melee. While running, jumping and rolling.

Use Wrathful Advance on a basic target or teleport, to guarantee red crits to erase stronger enemies and bosses in a few seconds.

Optionally, prime enemies just to get ~100 million damage numbers. Its possible to hit damage cap too, but its quite unreliable

PROS: Insanely strong damage output. Great 1v1, good crowd control.

CONS: Gets kinda boring...

Longer explanation:
As an [Excalibur Umbra] main, I can attest that this exact build helped me complete Steel Path solo and now even reach Level Cap

The basis of this build is three-fold:

First, the 100% status chance powered [Exalted Umbra Blade]. High Damage to single targets. It relies entirely on [Exalted Umbra Blade] as primary source of damage.

Second, the guaranteed 12+ times critical damage thanks to Wrathful Advance, granted by 5x Violet Tauforged Archon Shards, thanks to Primed Flow 500 energy.

Third, Building Electricity into [Exalted Blade] to utilise Melee Influence. This will help clear out groups and even rooms.

Recommended Exalted Umbra Blade build: https://overframe.gg/build/69648/exalted-umbra-blade/exalted-umbra-blade-build-steel-path-endgame-level-cap-guaranteed-red-critical-hits/

Summary
Transient Fortitude and Umbral Intensify to [Reach] 100% status chance thanks to Chromatic Blade and increase damage with [Exalted Umbra Blade], and help Wrathful Advance + [Exalted Umbra Blade] hit 300% Critical Chance for guaranteed Red Crits. Using Chromatic Blade, make sure the selected emissive element is electricity.

Steel Charge instead of [Growing Power] as it provides slightly more damage to [Exalted Blade] at this Strength level, and applies its bonus on the first hit. (Generally doen't matter much)

Power Drift to hit the power requirements

(Major Update 2.1) Umbral fiber, Umbral Vitality and Rolling Guard are the survivability mods. The Umbral mods boost your overall ability strength and damage.

(Major Update 3) Helminth: Replace Radial Javelin with Wrathful Advance from Kullevero. This is extremely significant for massive damage and the ability to basically eliminate bosses or very-high Steel Path Endgames.

(Major Update 4.1) Archon Shards. Thanks to the relatively recent nerfs to enemy armour, just build for all Tauforged Purple Shards to boost Critical Damage Multiplier

(Major Update 5) As of the 38.5 update, Exalted Weapons can equip arcanes. Big Thanks to those who mentioned that Melee Duplicate doesn't work with any crits higher than base (It's such a useless Arcane). I highly recommend Melee Influence, it combines well with Electricity to help clear rooms very quickly

For Arcanes, anything works. My preference is for more damage focus Arcane Fury and Arcane Strike. For those who have difficulties with survivability Arcane Reaper can slot in replacing either of the aforementioned Arcanes.

Flexible Mods:
If you don't like Rolling Guard, you can replace it with Adaptation for lower levels or Equilibrium + Synth Deconstruct for unlimited energy.

Recommended Load-outs:
Primary
Latron Prime with the Incarnon Genesis ; Superior armour strip, excellent against bosses.
Cedo Prime with Viral Primer

Secondary
Epitaph Prime; Great for priming bosses and being a sweat.
Lex Prime with the Incarnon Genesis; For fun

Melee - Something fast, fun. Doesn't really matter since Exalted Blade will be on most of the time. It's only a backup.
Nikana Prime; Combo Build

Companion
Panzer vulpaphyla; Must have mods Tenacious Bond + Bite, Reinforced Bond + Calculated Redirection, Viral Quills + Synth Deconstruct . Optional mods - Seismic Bond. Everything else is personal preference

Video Demonstration: