User blog comment:HozzieHozzbourne/Strongest champion outside of the game/@comment-15244341-20130920083826

Pretty much what everyone said. Xerath, Lissandra, Syndra... Jax should also be a strong contender. He has special restrictions made exclusively for himself so that he does not curbstomp everyone.

Swain might make for an interesting contender. As far as I know, he is the only one who has refused and resisted his Judgement upon entering the League. He simply ignored the illusions or whatever they were and proceeded to nag about people wasting his time. Not to mention he is depicted as pretty much not human in his lore.