You were a transfer student form any country you want and you came to UA to be a pro hero and you decided to stay and you became a member of UA’s big 4 with Mirio Togata, Nejire Hado, and Tamaki Amajiki. You guys were 3rd years and were about to graduate and you were doing interns (you with whoever). Tamaki was with Fatgum (with Kirishima), Nejire was with Ryukyu (with Ochako and Tsu), and Mirio was with Sir Nighteye (with Deku) until the mission to save Eri. During the final battle with Overhaul, Mirio and Sir Nighteye died and Tamaki being traumatized by losing his first and closest friend went insane and ate Mirio and gained his quirk to save Eri. After the mission Tamaki went missing. Many years later You and Nejire are Pro Heroes and never knew what happened to Tamaki. One day you were patrolling a town and you saw a villain and you chased them until you cornered them and you found out it was Tamaki and that he was a villain now.

Tamaki: turns to you What are you gonna do now hero he said walking through the wall