Assassins cannot deal damage to them even with Sneak Attack but insta-kill still procs time to time.
and Templars never use Arterial Strike on them.
These are at odds with the wiki article:
Phantom Warriors are still vulnerable to Sneak Attack and Arterial Strike, even though they are incorporeal creatures, advanced soldiers, especially Assassins, can deal a bit of damage to them, although not quite enough to seriously hurt the Phantoms.
Also Cronan doesn't use Deep Lash skill on them, at least on Steam version.
Are these the same on mobile?