Before this is marked as a duplicate, my question is more specific than the other one.

In the third book, when Harry has his wand on Black in the Shrieking Shack, he wants to kill him. He also clearly plans to use a spell because his wand was pointing at Black's heart, and when Crookshanks sits on Black's chest to protect him, Harry thinks:

So what if he had to kill the cat too? It was in league with Black.... If it was prepared to die, trying to protect Black, that wasn't Harry's business

If Harry was planning on using physical force to kill Black (which doesn't seem in character anyway - Harry bashing someone's head in?), he wouldn't worry about Crookshanks being in the way. And in that case, the cat's protection wouldn't make a difference anyway.

So if Harry was planning on using a spell, which one would he have used? Even if he knew about Avada Kedavra (which he doesn't until the next year), I doubt 13 year old Harry would be powerful enough for it to work. He didn't know Stunning, etc until next year, and he had no idea expelliarmus could knock someone out (the Snape incident happens later).

He seems very assured about killing Black. The only thing that seems to be getting in his way is his nerve. He seems like he knows what he wants to do.

"Harry raised his wand. Now was the moment to do it."

"-- but the footsteps were thundering up the stairs and Harry still hadn't done it."

"He hadn't done it. His nerve had failed him."

What spell could he have been thinking of, even if it may mot have ended working?

  • “I won’t blast people out of my way just because they’re there,” said Harry, “That’s Voldemort’s job.”
    – Tom Doyle
    Commented Aug 27, 2014 at 11:39
  • I think He was thinking of expelliarmus , He just wanted him to be killed (or punished) by MoM. But again , it's an opinion ..
    – Rajan
    Commented Sep 11, 2014 at 13:59

1 Answer 1



At least, I don’t know of any canon explanation of how Harry planned to kill Sirius (or if he even had a plan in mind). It seems a bit morbid a topic for J.K. Rowling to explain.

Personally, I’d be a little surprised if Harry had a specific spell or curse in mind. As far as I recall, he’s never had to kill anything with magic, so he’s thinking on the spot. Pointing his wand at Sirius’s heart sends a clear message – I am going to kill you – and gives him time to think about how he might actually do it. Of course, Lupin bursts in before he can finish the thought.

Now, would it be possible to kill Sirius with a third-year’s arsenal? I think so.

Sirius has been severely weakened in Azkaban and is currently unarmed; see my answer to Why did Sirius succumb to the Dementors without resistance? for more details. His defences are probably at a fairly low ebb.

It seems that first-years learn Incendio, or a similar flame-summoning charm. I’m no doctor, but a jet of flame directed at the human heart is probably lethal. Cast with enough force, I think Harry could kill Sirius. That would be my guess for how Harry would kill him, but it’s just a guess.

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