Demacia hasn't gotten a Champion lately. How about this?

I've got one in the Community Creations board that would definitely be an interesting addition to the Demacian lineup.

http://boards.na.leagueoflegends.com/en/c/fancreations/25lAeiAZ-yousoconcept-nephree-the-dark-crusader

Nephree's a dark knight Champion who uses a cursed sword's powers to uphold honor and justice, but she's under continuous threat of being corrupted/driven insane by the sword's curse. Gameplay-wise, she is an armor tank who specializes in taunting enemies and delivering punishing counter-blows, with her damage capabilities scaling off her armor. You might think "Rammus 2.0?", but she plays differently.

Check out the link above for more details.