A very well written ficlet. Tonks is scary It's interesting she has never made such a transformation in canon given that she can change the color of her hair to non-natural pigments. Not many people have purple or link hair, after all.
Ginny's revenge is in many ways, even worse. Pettigrew just died. Horribly, yes, but his pain is over. Draco has to live.
Interestingly enough, Voldemort's fear is death. Likely due to his rearage. Most orphanages in the early 20th century were not far removed from Dickens' tales. Most were run by the church, either Anglican or Catholic, and both of them proclaimed "God is Love", pounding the lesson home with the infamous 'rod'. In both faiths, "the wages of sin, is death", and following that, eternal hellfire. Harry chose his ploy very carefully.
Well done. Alorkin