Or is it technically impossible because it’s an aura?
Giving offensive auras like Night’s Chill or Vindictive Flame to trigger on hit devotion skills would open up interesting builds. Yet their chance to trigger would have to be adjusted accordingly lest they do not become over-powerful.
Well CoF didn’t see its chance to proc devotion effects lowered, and it can hit the whole screen.
I am too afraid to ask at this point but which constellation is the CoF?
It’s Curse of Fraility debuff from Occultist. I honestly wouldn’t be against some devotions being able to be attached to Night’s Chill. At least stuff like Assassin’s Mark maybe.
Oh I see. 
Well then the answer is of course no but let me answer a different question.
CoF can actually hit things unlike Veil of Shadow. So assigning a low cooldown devotion skill like Twin Fangs or Guardian’s Gaze on it is actually a very good idea.
We’re talking about Night’s Chill and not Veil of Shadow. Night’s Chill deals Cold and Frostburn damage to nearby enemies. And even then, Veil of Shadow actually hits thing too by reducing enemy’s OA and Total Speed.
I guess the main reason you can’t attach offensive devotions to Night’s Chill is probably because it’s an actual aura and not an attack. CoF counts as an attack because you have to cast it manually.
Yes, but I’m wondering if that comes from a technical limitation or from an oversight.
Back when Devotion was introduced, maybe they had a global logic like “all spells get offensive devotions, all auras get defensive ones”. Months later, COF OFF were allowed to use offensive devotions. I don’t remember when but COF and VOS also got the right to proc “on attack” spells. So we don’t know if Veil of Shadow (or Ulzuin’s Wrath) technically can’t use offensive devotion or just if it was kind of forgotten.
As long as we’re talking about Veil of Shadow/Night’s Chill getting the ability to bind offensive devotion procs to it, why not Vindictive Flame/Ulzuin’s Wrath too?
The answer is as pointed out above. They are technically buffs, not attacks.
Night’s chill uses the skill template “buffradiustoggled.” By adding that entry to the devotion config of Acid Spray (for example), Night’s chill will indeed proc. I just tested for myself, and can verify that it does work.
Awesome! Thanks a lot for testing dude! So that means you were able to separate the main skill and its modifier right?
Based on that, Lethal Assault or Deadly Momentum could be able to receive defensive devotion then.
My mistake - I actually should have said Veil of Shadow, which is of course the base skill that we attach devotions to. For some reason I just think of the entire skill as Night’s Chill. It doesn’t seem to be possible to attach devotions to modifiers, even if said modifiers are added to the devotion whitelist. It’s certainly possible that I may be missing something.
Ok so in your modded version, you have the choice to put either an offensive or defensive devotion power?
That’s right, and it works perfectly.
Great! I guess I need to learn how to mod now!
Elemental Seal ability that exists on rare (green) weapons can trigger off of Veil of Shadow/Night’s Chill. The only exception to the rule I have encountered so far. Maybe it is a bug; maybe it is by design who knows.
Yes any “on attack” proc can trigger off of Veil of Shadow. Just not devotions.
You learn something new everyday. 
This kind of aura is treated both ways in the game. For example Veil of Shadow can’t have offensive celestial powers bound to it, while Consumption of Agrivix or Pestilence can. All three are simultaneously buffs and attacks.