Muggles' Guide to Harry Potter/Magic/Unforgivable Curses

Muggles' Guide to Harry Potter - Magic
Unforgivable Curses
Type	Spells (curses)
Features	Result in automatic imprisonment
First Appearance	Harry Potter and the Goblet of Fire

Overview

The Unforgivable Curses are curses so powerful and so malign that use of them on another human being is grounds for immediate life imprisonment in Azkaban Prison.

Extended Description

The three curses that are classified as Unforgivable are the Imperius Curse, the Cruciatus Curse, and the Killing Curse.

Mad-Eye Moody introduces Harry and his class to these curses in Harry Potter and the Goblet of Fire. Ron identifies the first, the Imperius Curse, and Moody tells how that one had caused a lot of trouble for the Ministry: often it was impossible to tell who had been acting out of their own impulses, and who had been driven by someone else. The Cruciatus curse is named by Neville, who has reason to remember it as his parents suffered greatly under it. And the third, the Killing Curse, is named by Hermione; Moody mentions that it can't be blocked, and only one person is known to have ever survived it: Harry Potter.

Harry makes use of two of the Unforgivable Curses in the books. Dueling with Bellatrix Lestrange, he attempts the Cruciatus curse, with limited results; Bellatrix says that he has to really hate someone to make the Unforgivable Curses work properly, righteous indignation isn't enough. He also uses the Cruciatus curse upon Amycus Carrow, after he spits in Professor McGonagall's face, informing her that that was the reason why he did it. And when he is breaking into Gringotts, he uses the Imperius curse to control Travers, who has entered the bank with them, and Bogrod, the goblin who is ushering them down to Bellatrix' vault.