Have Riot ever created an evil Demacian yet? Or hints of something shady in Demacia?
Looking at their champion roster, the worst Demacia's gotten is just an over-confident french girl and maybe Jarvan who may or may not be influenced by something from some story-arc Riot left to collect dust years ago. Asides from that, all the world's evil seem to come from either Zaun, Shadow Isles, Ionia, or Noxus. Demacia seems a little too squeaky clean.
If evil does exist within the walls of Demacia, what kind of character would it be?
A corrupted clergyman whose mission is to wipe out all non-believers in some holy genocide? A corrupt government official? An over-zealous version of Vayne that extends his list of targets to "anyone not literally kissing Jarvan's ass"? If Demacian, it'd have to be someone who is Lawful Evil I suspect.
As far as preference goes, I'm kinda leaning on a corrupted high priest, pope, or whatever Runeterra's equivalent would be. Lives a lavish life-style, eats like a king, locks women away in his private chamber, blackmails royalty, leads genocides against meglings, impose ridiculous taxes, etc. Like High Overseer Campbell from Dishonored or that douche from Hellsing.
Or anyone from Guild Orzhov from MTG
God DAMN I loved Ravnica. Easily one of the best MTG expansions by a mile.