[Taqwus]

An Empoisoner... yes, back, especially if you're going to skellispam. Assuming he's not some weirdly heroic Empoisoner kitted out for hack and slash...

I've not found Star Children to be all that reliable as assassins, 'tho; the single Mind Blast is resistable and not especially lethal when not combined with other attacks to take advantage of the short paralysis. It's especially bad news if you end up trying to assassinate a skellispammer.

Should be noted that the etherealness of Elludian Stalkers is not associated with a Cloak of Shadows -- it's built into the unit type, so you can give them decent protection, resistance, or damaging-aura armor and keep etherealness. Or at least that's how it worked last I checked them. Nasty.