there are two ways to build [Xaku]: keeping [Xata]'s whisper or not. whisper is underrated because it lets elemental mods scale personal weapon damage. if you keep whisper, terrify is better than their 3:

• reduces strength requirement from 200 to 167 for full strip.
• more mobile, has no targeting requirement, and brings some cc
• twice the radius
  xaku's 3 is good on stationary objectives/corpus, and really annoying otherwise. even when i keep their 3, i just use magus lockdown for e.g. demolisher cc

if you don't keep whisper, use blind rage over transient fortitude. there are 2 standout subsumes:

• nourish gives energy, buffs turret damage, slightly buffs gun damage, provides some cc,
  buffs allies
• ensnare is best cc (barring maybe resonator or quiver), combos well with [Gaze] making a target invincible, basically mandates taking zenurik