Weapon platform Gara build without Helminth.
Brief mod explanations:
[Mending Splinters] and Combat Discipline will constantly trigger Archon Intensify for the bonus power strength, as well as Arcane Avenger.
[Flow] and Spectropsiphon help with energy economy. You can drop the latter if subsuming over her 3. Arcane Energize helps but is not needed. Fell free to switch out for something else.
Shattered Storm will spread the damage vulnerability effect from Splinter Storm when breaking Mass Vitrify with Shattered Lash.
Rolling Guard can help with survivability for higher levels. Consider Adaptation for lower level health tanking.
[Stretch] and [Continuity] provide some extra helpful stats.
Playstyle [Overview] and general tips:
Keep Splinter Storm active ideally on both yourself and companion, use Spectrorage for energy and cast Mass Vitrify before shattering it with her 1 to refresh 2 duration and spread the damage vulnerability effect.
Stat stick not needed as we are not building for Mass Vitrify nuke or Shattered Lash DPS, but the latter can work with Arcane Avenger.
Some Helminth suggestions over Spectrorage can be Nourish, Eclipse/Roar or grouping.
Two casting speed yellow shards are greatly recommended for this build.