Well I'm going all in with darkness. I haven't named him yet but for now "The Betrayed" will do.
He was a high level official in the Roman elite. Rising through the ranks quickly and effortlessly, it seemed he would be in line for Emperor in just a few short years. He had it all it seemed, life was good for ____. One night all of that changed when he found out something about his superiors he should not have. He had to do something - go public - show the people what they really were! But it was too late, they were more experienced at this than he was. Before he could get a word out about what he saw they took him. Publicly humiliated and blamed for crimes he did not commit, he was disfigured, banished and completely cut off from everyone he once thought of as family.
Years of brooding and isolation passed. Hiding from the world that took everything him, he began to go mad. Revenge was all he wanted. When a curious god came upon him and offered a deal - the power to carry out the most horrible vengeance imaginable - for a small fee; (Not that he was using it anyways) his soul would do the tick.
So yeah, he's like a Roman emo boi.
First pass at design - I'm going to feel a lot of this one out in the sculpt itself so I'm not too worried about digging into small details with these sketches.