In canon, Harry only ever tried casting spells on Voldemort twice, and both times it was Expeliarmis, and in both cases, Voldemort simultaneously fired Avada Kedavra, and in both cases, wandlore ended it in Harry’s favor (in the first case, it was because their wands share a common core, which may or may not be due to their magical link. This one is notable, because it prevented Harry from casting on Voldemort as much as it prevented Voldemort from casting on Harry, but without his wand, Harry was still vulnerable to Voldemort’s crucio. This effect was a flashier version of what happened in Azkaban, including a light show and images of the last few people Voldemort killed climbing out of his wand.)
Voldemort tried using Luceus’s wand in later books to get around the wand problem, but this failed for reasons that did not seem adequately explained (something to do with wand ownership?)
I expect Quirrell was using his Alder wand in Azkaban instead of Foldemort’s yew, in which case the connection in HPMoR presumably recurses a level.
If we use canon as a guide, if Harry touches Quirrell, it will cause them both pain (sense of doom), but to Quirrell it will do physical damage (Lilly’s sacrificial protection). I expect there to be less of an imbalance in Harry’s favor in HPMoR, but I didn’t expect the troll or the unicorns, so my HPMoR predictions aren’t so high confidence.
In canon, was there any reason Harry couldn’t cast a spell on Voldemort?
In canon, Harry only ever tried casting spells on Voldemort twice, and both times it was Expeliarmis, and in both cases, Voldemort simultaneously fired Avada Kedavra, and in both cases, wandlore ended it in Harry’s favor (in the first case, it was because their wands share a common core, which may or may not be due to their magical link. This one is notable, because it prevented Harry from casting on Voldemort as much as it prevented Voldemort from casting on Harry, but without his wand, Harry was still vulnerable to Voldemort’s crucio. This effect was a flashier version of what happened in Azkaban, including a light show and images of the last few people Voldemort killed climbing out of his wand.)
Voldemort tried using Luceus’s wand in later books to get around the wand problem, but this failed for reasons that did not seem adequately explained (something to do with wand ownership?)
I expect Quirrell was using his Alder wand in Azkaban instead of Foldemort’s yew, in which case the connection in HPMoR presumably recurses a level.
If we use canon as a guide, if Harry touches Quirrell, it will cause them both pain (sense of doom), but to Quirrell it will do physical damage (Lilly’s sacrificial protection). I expect there to be less of an imbalance in Harry’s favor in HPMoR, but I didn’t expect the troll or the unicorns, so my HPMoR predictions aren’t so high confidence.