I think to give any valid feedback, we need a rundown of what icons currently exist and what they stand for. Without that information, we're kind of shooting in the dark--this whole topic was founded on trying to decipher what we were seeing, because it wasn't immediately obvious.

Continuing from Lima's post.

When we realized the ability icons were confusing, we even tried to simplify by either showing whether it was an ability or attack which dealt the killing blow.

Ultimately, that's not the most important information to convey (pretty irrelevant actually), so we went with kill, streak, streak ended.

If these are the three things you want icons to represent, than I think I have an easy to understand pattern.

A kill is the normal crossed swords icon.

A killing spree is the crossed swords, but with the blades on fire to represent the spree.

Ending a streak would be the swords are broken, possibly with a bit of smoke coming off of them to show that the fire has been put out.

uhh pretty obvious

kill - guy gets stabbed
streak - naked guy running
streak ended - naked guy gets stabbed.

you're welcome

this is why we have adjudicators. +1 sir.

1 sword - normal kill, no streak
multiple swords - kill with streak (maybe an x5 or something for large number sprees)

killing spree ended - broken sword? idk. this one might be hard

I still think the skill icons would be best, increase the size a bit to make them more readable. Anyone who can't tell what it is at that point doesn't really care enough about the icons to begin with, so its moot if they don't know.

Heck, add a mouseover on the icon to show the skill tooltip even. This way, less educated players might even learn more about what other champions do.

Someone else mentioned using fire and ice to signify streaks and streak breaking respectively.

A kill could just be a sword, maybe a bloody sword.

Maybe you could have the portrait of the portrait of someone on a streak on fire, possibly correlate flame size/number of flames with streak size, and then have a broken kill streak have ice/frost around the person who's streak was broken's portrait. maybe something along the lines of say, the font used on an Ice Age 2 image (the blue/whitish one, GIS should spot it pretty easy).

Regardless of streak status, you would have the sword as the icon with only the portraits of those involved indicating streak/break status.

This, because it is simple and direct. Anyone can understand how it works, and you can glean all the useful information in a very quick glance. It also leaves the icon variable still available for other information to be added, if desired. Like:

I think you could show the source of the killing blow by using simple letter icons instead of the actual skill picture:

Q for their q skill
W for their w skill
E
R
P for passive
A for basic attack
I for item damage

That should look fine and not be too confusing.

Edit: I forgot towers and minions. Those would probably work as icons easily enough.

I'd like to see icons for ace, shut downs, triples, quadras, etc.