A general steel path build focusing on maximizing damage and survivability. Crystallize is subsumed for Roar as most things in steel path (at least up to and including level 220) will die almost instantly anyway, making it pointless to spend the extra time targeting crystals.

She is also a fantastic passive support frame. With this build, her 2 gives everyone 90% DR, her 3 gives everyone 240%+ increased status chance and 170%+ increased status duration AND strips armor, finally her 4 gives everyone 70%+ damage boost (increased to 90% with molt augmented maxed).

Just a quick explanation on her stats:

Ability Strength: 243%
225% is the minimum required to hit 90% damage reduction on cast of Preserving Shell
200% is the minimum to guarantee a drop of a health orb Fracturing Blast anything above that increases the chances of a second health orb being dropped
Generally more ability strength than this is not required, however since we subsumed Roar. Increasing our ability strength from 243% to 303% with Molt Augmented changes 72.9% bonus damage to ~90%

Ability Duration: 179%
There are a lot of abilities cast here to maximize your damage, so having more duration just makes the build feel so much better. At 179% duration, your ability durations are:
Roar: 53.7s
Prismatic Gem: 53.7s
Preserving Shell: 44.75s

Efficiency: 45%
Efficiency is irrelevant as we have [Equilibrium] which turns all our health orbs into energy orbs and we have a 100% chance of dropping a health orb and a chance of dropping a second health orb after killing an enemy hit by our 1.

Range: 160%
This affects primarily her Fractured Blast and Prismatic Gem range, but it also affects the range of Roar's buffing effect.

Archon Mods + Aura Choice
We strip armour through the use of [Archon Continuity] which applies Corrosive to enemies afflicted by Toxin. With Prismatic Gem, if you or an ally deals weapon damage within it's AOE, the enemy will immediately be afflicted by Heat, Cold, Toxin, and Elecricity, which will then proc Corrosive. This corrosive then has it's status duration increased by the effect of the gem.

In terms of aura, you can pretty much run anything, but I recommend keeping [Corrosive Projection] as it helps strip armour much faster.

Arcanes
I would consider Arcane Blessing mandatory as it saves us having to use [Vitality], it essentially increases our max hp from 500 to 1700 and since we drop so many health orbs, it maxes out extremely quickly.

Second arcane is optional, I prefer molt augmented for the extra roar damage, but feel free to pop on whatever you feel comfortable with.

Archon Shards
I'm still in the process of farming shards for her, but 2 emerald shards will help massively with armor strip. After that, I'm thinking either duration shards or cast speed as Roar is a bit of a pain to cast and locks you in place.

Synergies
If you don't have an AoE weapon, your Prismatic Gem will only target one enemy at a time. However, if you use your Fracturing Blast, the gem will target ALL enemies hit by your ability which will apply Impact, Slash, Toxin, Electricity, Heat, Cold, Corrosive to ALL enemies you hit. This is because the damage by Fracturing Blast is considered weapon damage so procs 3.

Your roar will also buff the damage of your gem

Your Preserving Shell damage reduction goes down over time if you don't get kills or assists. If you place your gem near teammates, their kills will grant you assists as the gem fires it's beam through walls and floors so will almost guarantee you an assist for each enemy your allies kill. If your DR goes too low, just pop your Preserving Shell again. Also note that Preserving Shell makes you invulnerable whilst casting it so you can use it to get yourself out of sticky situations.

Playstyle
Immediately use your 2 and ensure you keep it up throughout the mission as this is your primary DR.
Once you have enough energy pop your 4 and keep it up throughout the mission
Should you stay in one place for while (defense, mobile defense, survival etc...) drop your 3
If you see a big group of enemies, pop your 1. If you have your 3 out, this will melt enemies health bars.

Weapons
I like using a [Phenmor] as my main weapon as the incarnon feels really nice to use, but realistically you can use anything since your gem is going to give you so much extra damage anyway.

For my secondary, I'm using a magnetic [Tenet Cycron] built with radiation and corrosive. Because the beam jumps between enemies, it causes your gem to proc on multiple enemies at once which is really nice.

Demonstration

I've made a short video demonstrating how strong this build is even if you don't use your weapon. You can see by using all my abilities and proccing with my 1, I can melt level 230-240 steel path enemies without even using my weapon. Of course you can see at the end once you add a weapon into the mix, you can [Shred] any enemy with a short burst. Note that this is not a nuking frame, there are [Citrine] build that can nuke using Mecha mods if that's more your thing. This was more about general use, so it has some nuking capability, but not as much as a dedicated build for it.

I'm new to building, so if there are any improvements I could make let me know!