I would like to leave a suggestion that came to mind when I was playing Zed. I would like to see a visual indication (both Zed, his allies, and enemies can see it) of how much damage a enemy will take at the end of Death Mark. For example; say the enemy you use Death Mark on has 600 health and at the end of the duration it will do 300 damage, so half of that enemy's hp will be red showing that. This would give a Zed player a better idea of when to back of knowing his ulti is going to get the kill, how much more damage they will need, etc.

How do people feel about this?

With playing champions like that, you should be able to know when you are and aren't based upon skill level. To more experienced players, that would be like a smack to the face.

Why only Zed's ult and no-one else/no other ability?

Vlad's Ult does the same thing. Mao's Ult does damage when you end it based on damage done while it's active.

Play Zed long enough and you just get the feel for it. I was expecting your suggesting to be something like if Mark doesn't go off it refreshes the CD or something.

Necro'ing this thread somewhat to put in my suggestion for Zed.

I honestly think his ult could use one quality of life buff where if Zed's marked target dies before the ult detonates the cd is only put on cd for 6 to 4 seconds. Something to reward either good team play in the sense that the target dies before the ult goes off or you're just so ridiculously fed that you just do all the damage needed before the target dies. At least I feel in this change Zed will get that ability to have that slippery feel in a team fight and just being able to jump around and assassinate.