4 Forma 1 Umbra Forma
It has the most important things [Xaku] needs:
100% armor strip
A lot of range for Grasp of [Lohk] and [Gaze]
15 guns in total
Enough duration to not spam abilities every second
Efficiency not being under 100% to destroy your energy
You can replace Streamline with a normal flow for 459 energy/70% efficiency or with Primed Flow for 650 energy/70% efficiency but it will be needed another forma for [Primed Flow] to fit
Very good for any mission and to blast through enemies under lvl 100 like sorties or murmurs without even trying
Recommend using his 4th ability first, then stealing the guns
Subsumed abilities DO NOT get their duration frozen
[Xata]'s Whisper can be keeped or replaced with silence(50m 38.3s), ensnare(25m, 19s) or roar (61%, 62.5m, 38.3s)
Arcanes are up to you, but i recommend atleast Energize, second slot can be Strike, [Fury] or whatever you feel like it will be better