Holy hits immediatly after using an instant spell

[Lyzern]

If you use an instant spell after casting Holy (While the animation is occuring, before it explodes and deals damage), Holy will hit immediatly and the animation will still occur after that.

[Kaisha]

It's called animation cancelling and has been in the game since it started. WARs use it a lot by popping Brutal Swing to get Butcher's Block off quicker.