So, what are the mechanics behind Psi-Lance?

[szmind]

This is the only thing I cannot figure out or find reliable info on. I've seen "miss" for Ethereal's attacks so it is not 100%; neither is it will-test-based as I would expect something like "failure". So is chance to hit based on aim or will? How can I improve my chances to survive/withstand the attack? Should I boost will or get cover (weird) or suppress (not so weird)?

[fowlJ]

Psi Lance is the Ethereal's normal weapon, essentially a gun but with no ammo limit and a special animation. It hits based on aim but has increased damage based on the difference between the Ethereal's Will and the target's.

[szmind]

So taking cover decreases Ethereal's chance to hit with Psi Lance, right? That might be in line with my observations (as far as I can recall )

[fowlJ]

Yep.