I still think the fist guy in Ekko's teaser video is Augmented Singed.

Now I know Riot said it's not but look at it. The giant machine fist looks a lot like Augmented Singed's shield. He has the poison canisters on the back for his chem-trail, the frozen tube that Ekko slices through has the liquid singed shoots out in a puddle to slow you in game, and the flames you see coming from the exhaust remind me of Singed's ult. Plus the things Ekko says in game would make sense if he was saying them to singed. I don't know about you guys but I think it's Singed.