DISCLAIMERS:
*My preferred convenience build geared towards not needing to change anything while still being viable in the majority of game modes.
*Best paired with a high clearing weapon (not necessarily room nuking ones).
*Not specifically helpful for camping outside of Gloom support, but can be improved by Magus Anomaly through quickly spamming Transference + quick melee to draw enemies in 30m towards you, which is useful for a WIDE variety of scenarios.

OVERVIEW:

GAMEPLAY - Optimized for both facetanking and Hysteria usage with recommended occasional or dedicated melee use. Gloom is purposed to support defense situations and survivability. Rip Line being kept as it's useful for mobility, specifically climbing high areas or for quick directional momentum.

FLEX SLOTS - Polarized around aura, exilus, Streamline and Arcane Strike slots being interchangeable flex slots (anything is viable and aura forma is applied).

• Enemy Radar is personal preference, making it easier for everyone to find enemy group spawns (especially helpful in Survival).

• Primed Sure Footed generally preferred, replaceable with Handspring as the next best thing.
  No forma to hold varying mod polarities, e.g. Coaction Drift, Power Drift, Cunning Drift, Vigilante Pursuit, Firewalker.

• Streamline preferred mainly for ability recasting / spamming, more efficient Gloom and longer lasting Hysteria. Also very convenient in energy reduction sortie, allowing Warcry to be casted.
  Primed Flow can be fitted using Rage over Hunter Adrenaline and a lower ranked Adaptation depending on aura capacity.

• Change the arcane flex slot to fit your playstyle. Arcane Blessing for a near perfect health and armor ratio, but requires a Panzer Vulpaphyla with Viral Quills and Synth Deconstruct. Arcane Strike / Arcane Fury for dedicated melee buffs. Arcane Avenger for a more versatile weapon platform playstyle and Combat Discipline is not mandatory.

Other mods reasoning:

• The build can be viable (if considerably less convenient) without the semi-mandatory Arcane Energize as energy can still be gained from Rage / Hunter Adrenaline. This would often be less efficient in star chart levels because of all the damage reduction, gaining miniscule energy returns from it in non-endless missions, though at the same time there shouldn't be a need for high energy consumption at those mission levels. Using Streamline, Warcry can be cast with the energy you spawn with and held throughout the mission with Eternal War and Gloom can be easily maintained.

• Archon Continuity boosts the upkeep efficiency of both Gloom and Hysteria, but also offers longer Eternal War duration and gains capped at around 40 seconds, very rarely running out from lack of kills from delayed enemy spawns, nukers or inactivity. It's also useful for slowing bosses, e.g. Plains Thumpers, Lephantis, vault guardians. The mod will also force a corrosive proc along every toxin proc from Valkyr Prime Talons. For that, remove the generally used Shocking Touch and you are left with pure toxin from Primed Fever Strike and a flex slot for preference.

• Polarized zenurik slot as Eternal War is generally mandatory and can be swapped with Enraged for Disruptions.

• Adaptation improves facetanking considerably in long Endless / general Steel Path and most noticeably preventing health melting from toxin clouds and corpus beams.

• Hunter Adrenaline (marginally superior version of Rage in exchange for higher capacity drain) is mainly purposed for:
  *Endless infestation missions where energy is constantly being drained by the overwhelming amount of energy leeching.
  *Situations where energy orbs aren't dropping and / or Arcane Energize fails to trigger, which can happen occasionally.
  *Tight situations in high Endless runs where one hit is enough to refill your energy for Hysteria. This is especially useful for reviving allies, carrying points in arbitrations and moving through hordes so tight that they are basically a collision wall, to get to the arbitration drone, popping out of Hysteria for the kill and back in.
  *It has it's benefits over Energy Pads, mainly being functional while Gloom is used, whereas Pads are blocked by it.

ARCHON SHARDS: Highly recommended dedicating 2 slots to casting speed, with the rest being the "obvious" choice of melee critical damage or maximum energy for more QoL.