On the subject of unkillable units, last night I played a game against necrons and had a blob of warriors and lychguard protecting an overlord in combat and My archon must have deflected easily 40 shots. He alone tar-pitted almost half of his army hell bent on taking that objective.
Because of the shadow field as well, rolling them one at a time is very demoralizing for an opponent if no 1's come out. I am frankly disappointed in out Archon because he can't wound against anything reliably with that husk blade since we are basically rolling 5's to wound against T4 up, but as a shield for the kabal, that shadow field was impressive when it works correctly.
Rising Dark Eldar Archon
(1000+ pts and still building!)
2000ish points of Tau
(Falling in love with Deldar something fierce though.)
Also, Check out my podcast about the Tarot!The S&M Podcast