Soldier

"Profile reconstruction complete. Identification confirmed."

You are John Shepard. The first human Spectre. An orphan who grew up tough on the mean streets of Earth's super cities. You ran with the gangs. Fought to survive. And on your eighteenth birthday, you made it out. Joined the Alliance, who put your hard earned survival skills to good use in the Marines. They taught you new skills. How to use any weapon, how to turn any thing into a weapon, including yourself. They made you a Soldier.

Nearly a decade later, on the supposedly 'settled and safe' colony world of Akuze, your entire unit was ambushed and slaughtered by alien monsters called threshers. You barely made it out alive. Your unit, along with the entire colony on Akuze was destroyed that night.

Most men would be crushed by the survivor's guilt or jaded by the loss of their friends. Not you. The attack only made you harder, stronger. When the time came to take the planet back. You lead the charge and personally sent every single one of those fucking monsters straight to hell.