@Riot, We have to talk about Lux.
Okay. So everyone knows that Lux is well known for having an ultimate that has a ridiculously low cooldown. Even before the new runes came out. Even back in the day, you could grab a ton of CDR and have your ultimate way faster than everyone else.
However? This. This right here. This is... absolutely ridiculous. Let's just talk about a little interaction with two runes that I feel is what breaks Lux, making her incredibly strong late game during Summoner's Rift and practically unbeatable in ARAM.
Ultimate Hunter and Presence of Mind.
So, as we all know, whenever Lux gets a kill with her ultimate, it decreases it's cooldown by 50%. ...a questionable change to her, but I suppose it's satisfying when you're playing Lux and just raining lightbeams on everyone's heads. But when you throw Ultimate Hunter in the mix and getting that rune to max stack, it's 5% reduced on your ultimate which is reduced even further by 2% every stack, which stacks at 5. Which lowers her already ridiculously low cooldown by another 15%. This is all before you even grab a single CDR item. So right out of the gate, you have a ultimate that has a 15% CDR with 50% everytime you get a kill.
However, when you add 40% CDR to that equation, you have an ultimate that gets lowered to about 28 seconds... without even maxing out Ultimate Hunter.
However x2, when you add one particular rune to this, the math explodes into a shower of lightbeams that choke the very heavens themselves and that rune, is Presence Of Mind.
With every takedown you get, be it a kill or an assist, you shave off 10% of your ultimate cooldown and regain 20% of your maximum mana.
So the overall math altogether is, 40% CDR from items + 15% CDR from ultimate hunter + 50% CDR from resets with your kills + 10% CDR per kill/assist from Presence of Mind.
With fully stacked Ultimate Hunter and 40% CDR, your ultimate drops to 25.5 seconds. Half that whenever you get a kill with your ultimate, it drops to 12.8 rounding up from 12.75. But when you add Presence of Mind to that, it drops to.... 9 seconds.
An ultimate that deals about 1000 damage (late game) on a 9 second cooldown.
Test it out yourself.