Excalibur Umbra Build. Done how I like it.

NEW: Meta Excalibur Build. https://overframe.gg/build/362203/excalibur-umbra/immortal-excalibur-slash-dash-procs/

Aura is [Steel Charge]. If you want to do [Corrosive Projection], there's enough room left in the build for you to do so, it just costs an extra forma. This build it designed so that you can use any aura or exilus mod so that you can customize this to fit any needs you may have.

Exilus is [Primed Sure Footed]. In addition to being the most expensive Exilus mod (Which means ANYTHING could fit in this slot) it also allows you to use weapons with Self Stagger without worrying about that, and never get knocked down, which can mean death to [Excalibur Umbra].

The three Umbral Mods are a must on this frame. Three Umbral Polarities for Free make [Excalibur Umbra] an excellent statstick.

[Primed Continuity]. Radial [Howl] likes Duration, and it's a seriously underestimated ability. It also reduces the cost of our [Exalted Blade]'s drain.

[Adaptation] is the best defensive mod in the game. Absolutely can't go without it on most Melee or Tank frames.

[Streamline] is just basic efficiency. Takes down the cost of all our abilities. I've tested this fully, and [Fleeting Expertise] actually increases the drain cost of our [Exalted Blade], so [Streamline] is the best option.

UPDATE VEILBREAKER:

For Archon Shards, use Crimson for Duration or Strength. Don't bother with other archon shards on this warframe.

[Chromatic Blade] and [Transient Fortitude] are the most important mods here. You need over 200% Strength on [Excalibur Umbra] with [Chromatic Blade] in order for your Exalted Blade to have over 100% Status Chance, which is completely necessary for it. (Exalted Blade Build here: https://overframe.gg/build/233071/ ) Remember to use Orange / Red / Pink Emissive Colors for [Chromatic Blade] for heat.

Helminth Ability is Resonator instead of Radial Javelin. Resonator completely disables enemy AI, and is the best in slot if going endurance with this build. For regular content, this can be replaced with Roar, Warcry, Nourish, etc.

Arcanes are Arcane Avenger, for crits on our [Exalted Blade], and Arcane Energize. Energize does not need to be fully ranked anymore, as the rework to older Arcanes make it so that it has a 60% chance to proc across all levels. Level 1 or 2 is perfectly fine now.

A key part of this build is bringing a [Panzer Vulpaphyla] with [Pack Leader] and [Hunter Recovery] to help keep you healthy. Other types of pets are now viable with this build. You can take a [Smeeta Kavat] for crits and other buffs. Adarza for crit chance. [Dethcube] is the best sentinel for this build, as it generates energy.

Just go swoosh, have a good time, swoosh through everything. Star Chart, Steel path, nothing can stop you.