The Khati Sha event does indeed include two (2) of the van shir version of spiritual arcanists, however neither of those drop any loot. The loot items come from the grimling version of the spiritual arcanist -- image uploaded. Yes, there are two different mobs with the same name.
The NAME.... This guy is a suprise pop during the Quest for the Ward event. He pops upon the death of the Ward of Death/Life "Sometimes" and as a wrinkle towards the goal of gaining entrance to Khati the Twisted.
I wish I had more details to share. This event means ya got have atleast 6 full groups of folks that work well together. You have to split and handle the cell area (Ward of Life) and POT room Ward of Death, just to see if this guy will pop. He is an off shoot of the other two and done prior to going after the Ward of Spirits
Negative, he's a spawn during the Khati Sha the Twisted event. After you kill the Warder of Life/Warder of Death, you go deeper into the zone and come to 2 'a spiritual arcanist', both identical vah shir, each surrounded by 4 grimlings. None are aggro. Neither responds to talking, and a localized /say tells you that they're stuck there, and that one is a fake, etc etc etc. So basically you have a "Lady or the Tiger" choice -- killing the grimlings protecting the correct Vah Shir, lets you continue the Khati Sha event (opens the last locked door and spawns Khati Sha). If you choose the incorrect one, 1 of the vah shir falls to the ground, the other has 4 grimling spawn behind him, conning KoS. When the grimlings are killed, the arcanist changes from a Vah Shir into a large grimling and attacks. He has two terrible AE's, Grip of Mental Reality, and Grip of Mortal Reality. 1 is a big AC/ATK debuff, the other is a huge mana drain/mana pool tap/feeblemind. He hits for 900ish max, doubling, no ramps, no flurries, enrages at 10%. When dead, the loot listed above is available, but the Khati Sha event is over as Khati Sha does not spawn and the door will not open.