Character Analysis
Hungry Like the Wolf
Defense Against the Dark Arts teachers don't have a long shelf life at Hogwarts. They expire faster than a sliced apple in the refrigerator.
But out of all the DADA teachers Harry has had so far—Profs. Quirrell and Lockhart—Lupin is the best for Harry because he serves as the mentor figure he needs.
Unlike Dumbledore, who speaks in cryptic riddles, Lupin, while still uber-secretive, gives Harry practical support. He tells Harry memories of his parents, builds up his confidence to face his fears, and teaches him the Patronus charm, which might be one of the most important spells Harry knows.
Also, chocolate. Lupin loves giving people chocolate, which makes him amazing.
Almost as important as chocolate is moral support. Harry feels pretty dejected at the end of the movie, but Lupin talks him through it:
HARRY: None of it made any difference. Pettigrew escaped.
LUPIN: Harry, It made all the difference in the world. You helped uncovered the truth. You saved an innocent man from a terrible fate.
Harry's dad is dead. His godfather is on the run from the law. So Lupin steps in to be the father figure Harry needs, if only temporarily. Thanks for the pep talk, Remus. Now where's our Snickers?
The Curious Case of the Werewolf in the Moonlight
Sadly, Lupin's reward for being a loyal helpful is being forced into resigning from Hogwarts. What gives?
LUPIN: Well, it seems that somebody let slip the nature of my condition. This time tomorrow, the owls will start arriving and parents will not want, a, um, well, someone like me teaching their children. […] Besides, people like me are... Well, let's just say that I'm used to it by now.
Because this is a kid's fantasy film, Lupin's losing his job because he's a werewolf. But his forced resignation has overtones of homophobia—in less advanced times, teachers were routinely encouraged to quit because of their sexual orientation.
In fact, Cuarón even gives Lupin and Sirius' relationship some homoerotic undertones. They share a lingering embrace, and Snape comments upon how close they are:
SNAPE: You two, quarrelling like an old married couple.
It's also been remarked upon that Cuarón subtly uses Lupin's lycanthropy as an allegory for HIV/AIDS.
Yup: it's reasons like these that we think that Cuarón's Harry Potter film ranks among the best of 'em…and why Remus Lupin is one of the Potterverse's most enduring and fascinating characters.