Alastor Moody

Dumbledore trusts and knows the real Moody well enough to recognize that the man taking Harry away is an impostor. He locates and frees the imprisoned Auror.

Both men are associated with investigating Dark wizards and Snape’s office, but Sirius distinguishes Moody’s preference for capturing suspects alive from Crouch’s harsher methods.

As Harry’s Defence Against the Dark Arts teacher, Moody teaches the class about dangerous curses and stresses vigilance; he also checks whether Harry was hurt during the Malfoy incident.

The two teachers distrust and confront one another. Moody has searched Snape’s office under Dumbledore’s authority, while Snape resents the scrutiny and challenges Moody’s suspicions.

Arthur recently helped Moody out of a difficult situation at Moody’s home, and Moody speaks appreciatively of him to Ron.

Moody regards Bagman as foolish and unreliable, though he acknowledges Bagman was not knowingly involved with the Death Eaters.

They are fellow Hogwarts professors. McGonagall challenges Moody for using Transfiguration as punishment and insists that school discipline should follow proper procedures.

Moody recognizes Neville’s distress during the lesson on the Cruciatus Curse, takes him to his office, and lends him a Herbology book to encourage him.

The apparent Moody taking the teaching post is later revealed to be Barty Crouch Jr. impersonating him; Crouch Jr. has imprisoned the real Moody and taken his place.

After Draco attacks Harry from behind, Moody turns him into a ferret and bounces him through the air; he tells Draco he knows his father and will keep an eye on him.

Voldemort’s plan requires Moody’s capture and impersonation. Crouch Jr. and Pettigrew subdue the real Auror and imprison him in his own magical trunk.

Moody despises Karkaroff as a former Death Eater and believes he deserves to be returned to the Dementors rather than granted leniency.