Dumbledore tells Harry that Voldemort has used Dark Magic to save his own ‘soul’ at the cost of Myrtle’s life. So Harry knows of at least one Dark Ritual which needs a death as sacrifice, ie making a Horcrux.
Quirrell tells Harry that the darkest ritual he knows requires only a sword that has slain a woman, and a rope that has hanged a man—to summon death.
Since Harry knows Quirrell knows every Dark Ritual there is worth knowing, and one of the rules of Evil Overlords is to get immortality, Harry knows that Quirrell is not telling him about the Horcrux ritual. If he puts the ‘where to hide a Horcrux’ & ‘the lose 5 things’ bits together, he will know he can never kill QuirrellMort, since he’s unlikely to get to any of the Horcruxes anyway.
I don’t think making a Horcrux qualifies as a ritual. And if it did, it requires one death whereas the one Quirrell mentions requires two (albeit indirectly and with the possibility of them not being murders).
He probably is hiding some darker rituals, but I doubt the making of Horcruxes is one of them.
Also, he could be judging the ritual most terrible on effects rather than sacrifices, and Quirrel’s worldview obviously judges summoning Death, especially without the dismissal, as more terrible than making yourself some flavor of immortal.
Dumbledore tells Harry that Voldemort has used Dark Magic to save his own ‘soul’ at the cost of Myrtle’s life. So Harry knows of at least one Dark Ritual which needs a death as sacrifice, ie making a Horcrux.
Quirrell tells Harry that the darkest ritual he knows requires only a sword that has slain a woman, and a rope that has hanged a man—to summon death.
Since Harry knows Quirrell knows every Dark Ritual there is worth knowing, and one of the rules of Evil Overlords is to get immortality, Harry knows that Quirrell is not telling him about the Horcrux ritual. If he puts the ‘where to hide a Horcrux’ & ‘the lose 5 things’ bits together, he will know he can never kill QuirrellMort, since he’s unlikely to get to any of the Horcruxes anyway.
I don’t think making a Horcrux qualifies as a ritual. And if it did, it requires one death whereas the one Quirrell mentions requires two (albeit indirectly and with the possibility of them not being murders).
He probably is hiding some darker rituals, but I doubt the making of Horcruxes is one of them.
Also, he could be judging the ritual most terrible on effects rather than sacrifices, and Quirrel’s worldview obviously judges summoning Death, especially without the dismissal, as more terrible than making yourself some flavor of immortal.