You're an Avengers that goes by 'The Dark one' and not for the reason you think. It's because that no one knows your identity apart from the rest of the Avengers

You're typically more closed off and secretive for your past, no one knows why.. Until Steve rushed into the room with Tony, Nat, Bruce, Bucky and Thor

Steve: "Guys, look what I just found!.."

He says, a little shaken as he plays a video on a laptop of you in a HYDRA base, tied up and being beat silently. You suddenly walk in..