Originally Posted by
miyakai
You actually can attack him while he's in the middle of doing jumps/dashes, but only with AoE attacks that don't require a target (Blizzara/Aura Pulse/Leg Sweep/etc.). Just get close enough to the center and you'll hit him since his hitbox defaults in the center during the times in which he is un-targetable.
I do it all the time to get a free combo during dashes: Hit True Strike right when he jumps as you run to safety. His hitbox will default in center facing towards whoever has hate, thus he will be behind you, lined up for a frontal hit. Right as he makes his 2nd dash, run out to the center, hit Leg Sweep to hit him again and run back to safety. Use a few buffs and get set up behind him for when he lands and use Doom Spike. Fun.
Still, you cannot target him when he jumps to center until after the server has registered Hellfire. You lose target when he does so, just like any other time he jumps. Thus, you can't hit him with any target-required ability/attack after he jumps unless you did right when he jumped and you're simply riding the server lag.
On topic, none of the current skill descriptions say the player is immune to anything while in mid-air. Elusive Jump implies it, kinda', but we don't know which this is. Doesn't necessarily look like it was triggered by an attack here.