Tyrael player here - As long as a character doesn't have the text "Unstoppable" above them they can be interrupted.

Sweet guide, I follow this build pretty close but not exactly. For level 10 I get the Divine Shield, I think the Divine Storm radius is too small and I like saving my teammates as well as my own ass. For level 13 I only get Holy Shock if we are absolutely spanking the other team in hero kills. I usually go Shrink Ray to combine it with Benediction and 2 charges of Hammer of Justice for an insane stun-lock. This guide improved my Uther game alot, thanks.