Karthus - Have you forgotten him?
His kit is outdated. Waaaaay outdated. So many champions nowadays can just walk or use mobility out of his Q's, making him NEED a rylais or to be godly with the aim. His e? Shorter than autos on most champs. W? You nerfed the shred ratio forever ago and then stopped paying attention to it, and him. And there're so many shields in the game right now that his ult is either outhealed, outshielded, or ignored with a HG. Because HG is a shorter CD. He needs some serious work and updates since he's one of THE oldest champions. Maybe make his ult ignore shields. Idk.