**warning: the majority of the details about Peter Pettigrew come out in Harry Potter books 3 & 4, so if you don't want them spoiled for you, and there are huge spoilers for both, don't read past ... well, the first sentence. also, some of the details found here can also be found in my write-up on Sirius Black, as his and Peter Pettigrew's stories have very much to do with one another**
In
J.K. Rowling's
Harry Potter series, the character of
Peter Pettigrew aka
Wormtail is a very important one, playing key roles especially in
Harry Potter and the Prisoner of Azkaban and
Harry Potter and the Goblet of Fire. His nickname is
Wormtail because he is an unregistered
Animagus and can turn himself into a rat. As you will find, he was deeply involved in the murder of
Harry's parents and the events that conspired at the end of book 4.
As far as anyone in the wizarding world knows, except for a few select people who can't prove anything yet,
Sirius Black is a dangerous criminal, convicted on charges of murder and accomplice to murder: 13 counts of
Muggle murder (with one curse), 1 count of wizard murder (although all they could ever find was a finger, not the body), and accomplice to 2 murders-- those of
Harry's parents. Apparently,
Sirius had been
James and
Lily Potter's
Secret Keeper when they were on the run from
Lord Voldemort, so that only he would know their location. As it turns out,
Sirius had convinced the Potters to use
Pettigrew as their
Secret Keeper, unwittingly leading them straight into the hands of a follower of
Lord Voldemort.
Pettigrew had been not really a friend of
Sirius and the Potters, but more of a hanger-on, a weak follower-type, which is why he was so easily converted to the dark side. When he saw the chance to deliver the Potters to his master, he took the opportunity, little knowing that the incident with the infant
Harry would lead to the near-extinction of
Voldemort, while
Harry escaped the deadly encounter with a small souvenir, a thin lightning-bolt-shaped scar on his forehead that throbs and hurts and tortures him sometimes.
Sirius was the only one who knew that it was
Pettigrew who had betrayed the Potters, and he confronted him about this in public as the authorities were trying to capture
Sirius. However, he hadn't counted on such desperate cunning as
Pettigrew showed when he, in one deft movement, killed 13 bystanders with one curse and at the same time cut off his finger and turned himself into a rat. The point of this was to make it appear as though
Sirius was indeed the dangerous criminal who had betrayed the Potters, and he was crazy enough to take out 14 more people when cornered.
Now remember our good friend
Ron Weasley? He has a pet,
Scabbers, a scrawny little... rat. Yes, rat. That's right,
Peter Pettigrew aka
Wormtail had been living in disguise as
Ron's pet rat ever since he disappeared in that confrontation, leaving part of his body (a finger) to make it look like
Sirius had killed him with that explosive spell.
This all came out in an encounter that happened between
Harry,
Ron,
Hermione,
Professor Remus Lupin,
Professor Snape,
Sirius, and
Wormtail at the very end of
book 3. When the five people there who were on
Sirius' side (everyone except
Wormtail and the unconscious
Snape) learned the full truth, they attempted to bring
Wormtail into custody, but he escaped.
After his escape, he found his way back to
Lord Voldemort, as we learn in
book 4. He managed to capture an employee of the
Ministry of Magic,
Bertha Jorkins, and get important information out of her, after which she was killed. This information, which was about the
Triwizard Tournament at
Hogwarts, led to the death of
Cedric Diggory (a
Hogwarts student and friend of
Harry) and an intense confrontation between
Harry and
Lord Voldemort. This meeting served to bring
Voldemort to
full strength, as he made a potent potion from
Wormtail's hand and
Harry's blood among other things.
Thus
Peter Pettigrew played a key role in the return of
Lord Voldemort, which will lead to the ultimate showdown between good and evil in book 5,
Harry Potter and the Order of the Phoenix.