Well, this is my first champion design. Honestly, I think the abilities are a little bland and could use some revamping, but the Darkness system seems interesting. Champion is somewhat based on Rin Okumura from Ao no Exorcist.
The Darkness system is somewhat like the energy one. It regenerates fast and is used quickly. However, there's a twist: if your Darkness is full, it regenerates into your health as "Wither." It looks like a grey shield, but in reality, it lowers your maximum health. To get rid of it, you can use abilities to spend Wither as Darkness. This system makes the player balance plain spamming abilities, as Darkness is used up quickly, but also forces the player to use abilities at the right time, otherwise he is punished severely.
Background: Rin was always a problem child. When he was young, he did not make relationships with the other children around his neighborhood, as they risked a painful fate from the hands of Rin. He would fight constantly, so people would avoid him. However, he had only one person to rely on; a childhood friend named Syndra.
One day in adolescence, Rin sees a group of people his age hunting for the local birds. He experiences the bloodlust of humans, as the group grotesquely dismembers the bird, limb from limb. Infuriated by their acts, Rin attacks. Right before the blow, a black veil impairs his vision, and he faints. When he is awoken, before his eyes laid a strange scythe-like object, as well as the scattered remains of the kids whom he had attacked before.
Terrified by the grotesque scene, Rin runs off to find Syndra, who had been practicing magics for quite some time. Little did he know, Syndra had recently killed her master, and was set for vengeance. The reason for his transformation, revealed by Syndra herself, was because of the traces of evil magic left on Rin, which materialized once he had impure thoughts. Infuriated once again, he lunges at Syndra with his newly formed weapon. She smiles and disappears. Rin had a new goal: to stop Syndra's devilish plans of murder and destruction, and to recover his old self. This could only be achieved in one place; the League of Legends.