It can’t be blocked by raw magic (Protego and similar) but what prevents Actio, Wingdarium Leviosa or Free Transfiguration to be used to create a physical barrier to block the spell?
Nothing. Indeed, Dumbledore blocks the killing curse in canon (Order of the Phoenix) by animating a statue to jump in front of it.
So if AK is in any way unblockable, it is unblockable only by magical means.
Nothing. Indeed, Dumbledore blocks the killing curse in canon (Order of the Phoenix) by animating a statue to jump in front of it.
So if AK is in any way unblockable, it is unblockable only by magical means.