DeathFireTouch: Not applied to some abilities? Purposefull or Accidental

Ezreal's Q applies on-hit effects. You would find that Gangplank's Q has the same result.

Abilities which apply on-hit effects don't apply on-spell effects.

Basically, if the ability doesn't apply the slow from or the burn from , it won't apply Deathfire Touch.

It does not. I do not know -why- they chose to do this, actually. Many champs have linear skill shots like him, usually on low CD's too, but for some reason, they chose to change it so his Q didn't apply it. It applied it for the first week or two of the changes hitting the PBE, but I didn't play Ez as much after that since with it he seemed to be doing well. I put more focus on trying to see what Corki did well with (They never made his passive function with Trinity, so I was seeing if I could replace the Trinity). I was a bit shocked when I got into a game as AP Ez and my Q wasn't applying the DFT, lol. I was just glad I was using AP Ez 'cause AD Ez would never have even proc'd it.

I'd like resolution on this because as the mastery reads, it's a "damaging ability" on hit is a whole different matter after the fact. It's still a damaging ability.

The reason it works like this is due to the way they're is coded. In order to apply on hit attacks the ability needs to resolve as a basic attack. Since it counts as a basic attack when dealing damage it bypasses any code that would apply effects for KY being an ability.