Had Voldemort been restrained?
Although most people had not noticed Ron's Joint Spiders at that moment-the things were black and hardly stood out against Voldemort's all-black clothing-everyone noticed that something was clearly wrong with him.
"Master!" Bellatrix cried out. She had not been this anxious or agitated even when her husband had been brought down and captured. Ignoring Kingsley, with whom she had been locked in combat, she lunged toward Voldemort, clearly intending to help.
Several other Death Eaters did the same.
If anyone still had the attention to spare for the Death Eaters' precise movements, they would have noticed that almost all those who ignored the other attacks and rushed to Voldemort's rescue were people he had freed from Azkaban.
Meanwhile, those who had never been to Azkaban or had been released early-the Death Eaters Harry had once seen in Riddle Graveyard-each seemed somewhat hesitant.
The few wizards who tried to rescue Voldemort did not manage to get through.
Previously, Voldemort had kept most of the Order of the Phoenix and Ministry of Magic forces occupied, leaving only a small number of wizards, slightly more than the Death Eaters, to engage them. Now, however, Voldemort seemed to have been restrained all at once, and his magical output plummeted.
Although they did not know what had happened, the wizards from the Order of the Phoenix and the Ministry of Magic still instinctively began intercepting the Death Eaters who were trying to help him.
Though these Death Eaters were exceptionally powerful, they could not overcome the opposing side's numbers. Not one of them could get through.
Meanwhile, all four of Voldemort's limbs were controlled by Joint Spiders, leaving him unable to wave his wand and, for the moment, unable to use magic. Even so, most of the attacks from the Order