This has been floating around for awhile. We don't know if this will be a skin or a new champ. Some ppl think its for Lunar Revel Cait, to which I say nah. I could see a Kalista Skin maybe, but it looks interesting. The Korean Twitter, or was it facebook? I dun remember. One of those had some lines for each one basically about how the character's trait (Garen's heart and soul for his country, Vi's tough gloves and determination, Sona's music and support powers, and Zed's shadow illusion and evasion) weren't enough to stop this Deadeye, as they each get taken down. It's worded almost like an epitaph for each, however.
I'm betting a new marksman with a focus on debuffs, or maybe a ranged support/fighter with focus on target weakening or something.