INTRODUCTION

This is a gloom [Banshee] (or gloomshee) build that combines the extreme slow offered by gloom to lengthen the stun of silence while allowing you to carefully target sonar spots for extreme damage. Silence has an innate stun duration of 2s, which can be extended up to a maximum of 40 seconds at 95% slow. Sonar is a huge multiplier to damage as long as you can hit the spots, and up to two sonar spots can overlap to multiply together (e.g. at 200 strength, two sonar overlapping gives 100x damage multiplier). [Resonance] augment is optional but nice quality of life allowing Sonar to self propagate as you get kills via sonar spots, meaning you don't need to recast Sonar very often. Sonic Boom is also optional but helps armor strip priority targets eg (acolytes, demolysts, thrax) for even faster kills.

PLAYSTYLE

1. Activate both gloom and silence (optional - get headshot to activate pax bolt for +30% str +/- [Growing Power] for +25% then activate gloom for higher slow values)
2. Keep silence active at all times for stun and preventing special enemy abilities
3. Whenever shields break, roll and cast sonar to regenerate shields completely to reset shield gate
4. Stack multiple casts of sonar when fighting an enemy with damage resistance e.g. lich/sister/acolyte

Here is a video demonstration of the playstyle:

.

BUILD SPECIFICS

Duration
Positive duration gives decent sonar and silence durations and helps reduce gloom drain costs.

Efficiency
Maintain neutral efficiency for shield gating, so a single cast of Sonic Boom can restore 37.5 shield giving 0.7s i-frames while a single cast of Sonar can restore 75 shield giving 1.33s iframes (without augur mods)

Range
Positive range is nice to [Extend] the range of gloom, but too much range is actually detrimental for silence since the stun only lasts 2s outside of gloom and about 8s in gloom, and you need enemies to exit then re-enter silence range so they can be restunned. This is made easier by having a lower range. Since silence has a longer range than gloom, enemies will always be subjected to silence first before gloom meaning gloom has a slightly reduced effect on the stun, particularly if you travel slowly.

Strength
Strength affects both the sonar multiplier and gloom slow so we do want this as high as possible without losing too much functionality. Gloom 95% slow cap is achieved at 272% str and Full Strip from [Sonic Fracture] is achieved at only 143% str. [Resonance] augment allows self propagating Sonar to benefit from the strength of the inintial cast, meaning you can use Molt [Vigor] and conditional strength boosts to lock in strength values.

Flexible slots
[Catalyzing Shields] and Rolling Guard are flexible for each other. Catalyzing shields allows casts of Sonic Boom and Sonar to give more effective i-frames per cast, while [Rolling Guard] gives iframes and status cleanse with an 8s cooldown. Both are up to personal preference.

The augments [Resonance] and Sonic Fracture are both flexible options that are interchangeable for Streamline or more strength eg Transient Fortitude/Augur Secrets.

Exilus
Preparation - best option for speedrunning exterminates/lich missions, can keep mod at rank 8 since your energy will start at max
Power drift - to get higher slow
Primed sure footed - best option for everything else, particularly if you plan on using explosives

Aura
Brief respite - to allow sonar to reset shield gate along with augur mods

Arcanes
Either Molt Vigor and/or Molt Augmented to provide strength to hit max gloom slow (need 272% str), and boost sonar

Since headshots become much easier with gloom, arcanes that trigger on headshot are good:
Consequence - faster parkour
Pistoleer - ammo efficiency
Precision - pistol damage
Rage - primary damage

Archon Shards
2 Amber Cast speed shards makes spamming of Sonar and recasting of Silence extremely quick.
3 Crimson Strength shards gives up to 45% strength with Tauforged, meaning you can drop Molt Vigor or Molt Augmented for something like Arcane Aegis/Energize

ARSENAL

Companion
[Dethcube] with Energy Generator is the recommended companion so you are able to generate an energy orb roughly every 10 kills. Build: https://overframe.gg/build/224301/dethcube-prime/cube-of-deth-health-energy-orb-generation/

[Helios] is also a great sentinel when not using an armor strip subsume. [Helios] can use [Vicious Bond] to give passive AOE armor strip as enemies get damaged by abilities and can also use Seismic Bond which gives a free 30% efficiency with near continuous uptime. Helios Build: https://overframe.gg/build/542050/

Secondary
Pax bolt is great for giving a bonus 30% strength outside of mods, which can be snaplocked by gloom. Note that channelling abilities like gloom do NOT snapshot efficiency. This can be used on secondary kitguns like [Tombfinger], [Catchmoon] or [Gaze].