It move, it dies.

Xaku shoots at anything that moves with it's 0-Form Perpetual Motion Cannon.

If you want more healing, you could switch [Augur Reach] for Equilibrium and revert to a lower version of Flow. (388 energy required to cast all skills)

The actual build starts here

Passive; 25% chance to ignore damage from bullets. 25% damage reduction to area damage and status effects.
You can [Reach] 100% evasion with The Vast Untime and the effect of the Carnis set.

[Xata]'s Whisper, Grasp of [Lohk] and The Lost have their duration timer halted when The Vast Untime is in effect.

=> Empower; Helminth ability; Buffs ability damage for the next ability used (Pair with Grasp of Lohk)
Strength
50%
Duration
N/A
Range
N/A
Drain
38.75

=> Grasp of Lohk; 0-Form Perpetual Motion Cannon (Each individual gun has a fire rate of 1)
Strength
11.550 (Multiplied by the enemy's level. Reduced by armor)
Duration
18.6 (Timer halts when The Vast Untime is in effect)
Range
39.8 (Grab range)
21.2 (Fire range)
15.9 (Max targets)
Drain
77.5

=> The Lost (Check https://warframe.fandom.com/wiki/The_Lost for more info)
Strength
N/A
Duration
N/A
Range
N/A
Drain
116.25

=> The Vast Untime; Reduces resistance to Void damage and sets passive evasion to 75%
Strength
2508
50 Void resistance (On enemies hit when activating the ability)
52% slow (On enemies hit when activating the ability)
20% Movement speed
Duration
38.8
Range
66.3
Drain
155