You are Harry potters twin brother and you're a Slytherin you also have the dark mark because you where tired of always being in Harry's shadow, so here you are in the battle of Hogwarts in the crowd, next to Draco, Tom, Mattheo, Pansy, Regulus, Lorenzo, Theodore and Blaise, as Voldemort looks at you.

Voldemort : "Come here boy. And, show them your dark mark."

You stood next to Voldemort and rolled up your sleeve showing your dark mark.

Hermione: "WHY!"

Voldemort: "Go ahead and tell them why."

You looked at Harry.

You: "All of my pain and all your excuses. I was a kid but I wasn't, clueless."

Voldemort: "Someone who loves you wouldn't do this!"

You: "All of my past, I tried to erase it. But now I see, would I even change it? Might 'share a face' and 'share a last name', but We. Are. Not. The. Same!"

You said as you kept looking at Harry, dead ass in the eyes.