I notice that Quirrell no longer needs to transform into a snake to speak Parseltongue, which is suddenly very plot convenient (he doesn’t need to stop pointing a gun at Harry). I reasoned that he needed to do that before in order to keep a cover of Quirrell not being a descendant of Slytherin (which would increase the likelihood Harry would connect the dots that he is Voldemort), therefore he pretended to always need to turn into a snake in order to speak Parseltongue (pretended he wasn’t a natural Parselmouth). But then there is this bit from Chapter 49:
Quirrell in snake form: “This iss mosst ssecure way to sspeak. You ssee? No otherss undersstand uss.”
Harry: “Even if they are ssnake Animagi?”
Quirrell: “Not unlesss heir of Sslytherin willss.” The snake gave a series of short hisses which Harry’s brain translated as sardonic laughter. “Sslytherin not sstupid. Ssnake Animaguss not ssame as Parsselmouth. Would be huge flaw in sscheme.”
Therefore, Quirrell just confessed to Harry that he is, in fact, a Parselmouth on top of being a snake Animagus, since he just said (in other words) that being a snake Animagus does not automatically grant the user Parseltongue even when in the snake form; one has to be a true descendant of Slytherin. This invalidates my reasoning. Is there a satisfactory explanation for this contradiction?
Edit: turns out that with “Not unlesss heir of Sslytherin willss”, Quirrell meant to say that Harry himself grants any snake the capacity to speak because Harry is an heir of Slytherin. The ambiguity threw me off.
“That spell of cursed fire. I don’t suppose it’s a sacrificial ritual that even a child could use, if he dared?”
The Defense Professor’s lips twitched. “It requires the permanent sacrifice of a drop of blood; your body would be lighter by that drop of blood, from that day forward. Not the sort of thing one would wish to do often, Mr. Potter.
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One drop is roughly 1/20th of a milliliter. Blood donations routinely take 500 mL of blood from people without immediate ill effect; only some people get dizzy. It would take 10.000 such rituals to reach the negative effect of a single blood donation. Albeit there is of course a difference in that the latter’s volume loss is quickly recovered by the body after drinking some water, which wouldn’t happen with the ritual. Still, I doubt any ritual would be completed anywhere close to 10.000 times, making the permanent blood loss penalty trivial. Quirrell’s line failed to scare me in the slightest.