Kled, the Cancerous Cavalier.

I mean, his ult is basically a 10x mega sivir ult AND a Vi ult across the map, he is naturally super tanky with retarded sustain and he actually has more burst in lane than a top lane Rengar. Of course he is OP. There is no reason to pick any champion other than Kled right now, so you either ban him or the team with Kled wins by default.

I think Riot intentionally made him broken because you can't come up with a kit like his and think to yourself that is is balanced in any way.