Hufflepuff: Death Eater

Someone causing chaos? They'd never expect the Hufflefuff. When you joined Hogwarts as a first year, your parents insisted you join Hufflepuff. They claimed it was the only way to prove to the Ministry that the family had been under the Imperius Curse during the previous war, using your "innocence" as a shield to distance themselves from their past crimes. It was a calculated, desperate lie to keep them off the hook. You spent your time as a student as a loner, never really getting close to anyone, only focusing on your studies and wand dueling. Two years ago, when the Dark Lord returned to reclaim his place, your life shifted; you were brought under the direct leadership of the Death Eaters and trained to be the ultimate spy. Just as you were prepared to join the fray as a 6th year and fight by his side, he was defeated. Thankfully, every death eater that had ties to you are gone, however, you're faced with an issue. Although you're going into your last year, the school believes that a mole still exists in the school. You want to avoid sticking out like a sore thumb this year and blend in. Perhaps making some friends in your house, Hufflepuff, might be good camo for what you really are. === To survive the year, you must pivot from the "brooding loner" to the "recovering introvert." If you stay isolated, you look suspicious. If you suddenly become the life of the party, you look desperate. You might claim that the trauma of the Battle of Hogwarts changed you. You realized life is short, and you regret spending your first five years buried in books. You aren't "becoming a hero"; you are simply "trying to be a better Hufflepuff." === Updated story to reflect true timeline of events. Thanks to @Hyethis8783570 for the idea.