So I just wanted to mention that Darius gets wrecked vs Zed and Zed gets wrecked vs Kayle/Poppy(or anyone who can go invulnerable or block damage Jax, the hourglass item).

I want people to try it out and confirm because it sucked when it happened to me ingame and these are 2 different situations.

So I was playing Darius using the new skin Bioforge Darius and I ulted Zed a split second before he ult'd me and he went invulnerable and I used my ult on him, now the case here is that my ult recharged and let me use it again. The reason I bring this up is because Darius vs Kayle(when kayle's ult is in affect) Darius's ult goes on cooldown and does not damage Kayle, but when Darius uses his ult on Zed during Zed's ult it recharges.

Now the other issue is when you use Zed and ult on Kayle or someone using zhonya's hourglass. When Zed ults them and they go invulnerable he gets frozen. Now if this happens to you don't panic just use your w and move to your shadow and you will be able to move again. I'm not sure why this happens but I've been stuck twice when using his ultimate.

Please confirm this if you have the time and don't just do it once and say it doesn't happen(the Darius ult might be glitchy on Bioforge Darius I honestly don't know).

In the first situation, did your ult actually inflict damage and then recharge? Or did it just "fizzle" and not go on cooldown?

If it's the latter, that's simply because Noxian Guillotine has a "wind-up" time before it actually executes, where Darius can be interrupted. I've seen a Darius get hit by Cass's Petrifying Gaze midair before, and it cancelled his ulti (because it was in the "wind-up" phase).

Well it wasn't a silence or stun it went through with the attack and it was just me and Zed in a brawl in the jungle nobody else, I used my ult and he used his and I ended up executing the attack but it didn't make that impact noise which I think is the "fizzle" you are referring to. I don't think Zed has a silencing move just a slow so how it happened I'm unsure. Again, it showed the whole skill executing but the noise was not there except when I started the ult(just repeating to clarify what I'm trying to say). I wonder if he used his w and moved away which canceled my ult?

If the target becomes untargetable his ult deals no damage and refreshes. It is the same with many other situations

If Darius fail to kill (in the case of Kayle ult and other immunity, ult will fail 100%) it will go on cooldown, if it fail to "hit" like being fizzled by Zed ult, or Vlad/Fizz Troll pool/pole, your ult won't be used or put on CD. Hourglass will not put your ult on CD, doesn't do it with skarner ult, shouldn't do it with Darius R.

Kayle doesn't become untargettable, she becomes invincible to damage and CC.

The ult didn't "reset". It was just never actually cast. Just because the animation may or may not have initiated doesn't mean anything about the ability's actual logic counterpart.

All abilities don't go on cooldown when you use them against someone who becomes untargettable because you don't actually USE them, you just try to and fail, and sometimes the animation might play out anyway due to the engine not catching up fast enough.

Also, Ciderhelm has tried Zed's ultimate on targets right before they become untargettable (Fizz's playful trickster) and has found that Zed will still travel to the target and place a shadow behind the target while not being able to damage that target for the duration that they are untargettable.
http://www.youtube.com/watch?v=vk4nV...ailpage#t=489s

However, I find the Zhonya's glitch interesting, as it seems to be the same exact disjointment that happens when you cast Zed's ult on Sivir while she is spell shielding.
http://www.youtube.com/watch?v=vk4nV...ailpage#t=489s

It is clear that Zed is still in development, for whatever reason, a kill using Zed's Ult will credit Akali with an assist.
http://www.youtube.com/watch?v=vk4nV...ailpage#t=484s

Cheers.