Strange teaser on Zed, Sona, Garen and Vi

I want to say it will be some kind of team skin theme, it's only missing and ADC and otherwise these champions have nothing to do with each other lore wise.

I know everyone thinks it's a skin and all, but I disagree. If it was I mean Project Zed already came out, so did Demon Vi. So I would disagree with the whole skin theory. I think it has to be a new champion, I know Illaoi basically just came out, but that's my only theory right now. I also think that it is an ADC champ due to the Vi: Jungle Sona: Support Garen: Top Zed: Mid So that basically only leaves ADC. That's my only theory right now, I'm sure a lot more will be found out once the other teasers come out.