One of the dangers of being a Death Eater was the constant threat that eventually they were going to be placed under a punishing Cruciatus Curse. Before the Dark Lord began to weaken, he enjoyed casting it on his followers himself. He loved the screaming and the begging for mercy. It always made him feel more powerful. In twenty years, Hermione lost count the number of times she writhed under the spell. Bellatrix might have been the first to cast it on her, but she was far from the last. Even that wasn't comparable to the pain coursing not just through her arm any longer.