Riot has been experimenting with different ways to introduce new champions for a while now, and the most recent champion came out a couple weeks ago with a pretty sweet music video:
They went out and got the lead singer from Djerv, a Norwegian heavy metal/rock band, to do the vocals. I think it's pretty great!
I finally got around to trying the champion out today (I built up enough IP to buy her at the 'no longer brand new' reduced price) and she feels good. I rarely got to play against her in games because she seems to get banned a lot. This tends to happen with new champions since people who don't know how to deal with them would rather just ban them than lose to them even if they aren't necessarily too good. Often they are too good because the test server isn't the best place to find a competitive balance, but sometimes it's just unfamiliarity.
I have a feeling she may be too good, and it's mostly because of her passive that basically does nothing for the vast majority of the game. What it does is gives her a massive speed boost for a short period of time after killing a turret or champion. So it feels like she should be able to hang back safely in the big team fights and then hunt down all of the wounded enemies trying to run away at low health. She just needs to get one of them and she should be able to get them all. It helps that her ult has unlimited range so there's even a chance she can pick one off at quite a distance and then use the speed boost to close on the others.
She doesn't have an escape which is rough for an ADC, but she does have a pretty good slow and a root wall. Her other ability drains mana on each attack to make her autoattacks do AoE damage. I've only played the one game against bots so far to get a feel for it, but I never had mana to use that ability and her low cooldown high damage slow nuke. It makes me wonder if maybe she should build mana of some kind... Like a Manamune! I remember wanting to build that on Ashe back in the day to fuel her mana draining autoattack and eventually discarded it because it was a terrible plan. But Manamune has been buffed since then, and AoE damage with extra range is better than a slow anyway... Maybe it's worth a shot!