I agree that legilimensed Sprout’s magic is activating the sense of doom. But the troll was not legilimensed, so there’s no reason for the sense of doom to activate.
I may be wrong, but intuitively it seems that when Voldemort causes Sprout to cast a spell, that spell counts as originating from Voldemort, not Sprout—and that is what makes it activate the sense of doom. Whereas the troll was acting on its own accord, and so didn’t activate the sense of doom.
I think Solipsist was trying to say that if Voldemort using Sprout to cast a spell counts as originating from Voldemort, then if Sprout (or some other Imperiused individual) cast a spell on the troll’s skin, then Harry shouldn’t have been able to touch the troll. Before, it was assumed that Harry was able to touch the enchanted troll (its skin had been enchanted to resist sunlight) because Voldemort hadn’t directly enchanted it (Harry can’t touch things Voldemort enchants, see the broomstick escape from Azkaban) but used an Imperiused confederate. Now, however, it seems that using the Imperiused confederate does not negate the issues arising between Harry and Voldemort’s magic.
An alternate interpretation is that Voldemort was strengthening a few of the spells that Sprout cast, as well as the spell that Tonks used to win the battle, and this use of his own magic was what caused Harry’s doom-sense to tingle. If that’s the case, then there would be none of his magic on the troll.
This is a very good point. Possibly premature answer: the Dark Lord Tom hired someone else to enchant the troll before sneaking it into Hogwarts. Then he cast a spell on the hireling.
I agree that legilimensed Sprout’s magic is activating the sense of doom. But the troll was not legilimensed, so there’s no reason for the sense of doom to activate.
I may be wrong, but intuitively it seems that when Voldemort causes Sprout to cast a spell, that spell counts as originating from Voldemort, not Sprout—and that is what makes it activate the sense of doom. Whereas the troll was acting on its own accord, and so didn’t activate the sense of doom.
I think Solipsist was trying to say that if Voldemort using Sprout to cast a spell counts as originating from Voldemort, then if Sprout (or some other Imperiused individual) cast a spell on the troll’s skin, then Harry shouldn’t have been able to touch the troll. Before, it was assumed that Harry was able to touch the enchanted troll (its skin had been enchanted to resist sunlight) because Voldemort hadn’t directly enchanted it (Harry can’t touch things Voldemort enchants, see the broomstick escape from Azkaban) but used an Imperiused confederate. Now, however, it seems that using the Imperiused confederate does not negate the issues arising between Harry and Voldemort’s magic.
An alternate interpretation is that Voldemort was strengthening a few of the spells that Sprout cast, as well as the spell that Tonks used to win the battle, and this use of his own magic was what caused Harry’s doom-sense to tingle. If that’s the case, then there would be none of his magic on the troll.
This is a very good point. Possibly premature answer: the Dark Lord Tom hired someone else to enchant the troll before sneaking it into Hogwarts. Then he cast a spell on the hireling.