Why did Peter Pettigrew have the Dark Mark?

Question

The Dark Mark was a magical tattoo given by Voldemort to his inner circle of followers. Not all Death Eaters had one: for instance, the werewolf Fenrir Greyback was not considered worthy of it.

Although Peter Pettigrew was very useful to Voldemort in the year following his escape from Sirius and Remus, he was always regarded with contempt not only by Voldemort but also by other Death Eaters:

"Your devotion is nothing more than cowardice. You would not be here if you had anywhere else to go."
^{-- Voldemort, Goblet of Fire}

"Well, Wormtail's here, but we aren't counting vermin, are we?"
^{-- Snape, Half-Blood Prince}

BUT we know that he had a Dark Mark, which must have been given to him during Voldemort's first reign:

Voldemort bent down and pulled out Wormtail’s left arm; he forced the sleeve of Wormtail’s robes up past his elbow, and Harry saw something upon the skin there, something like a vivid red tattoo — a skull with a snake protruding from its mouth — the image that had appeared in the sky at the Quidditch World Cup: the Dark Mark.
^{-- Goblet of Fire}

Why did Voldemort let Pettigrew into his elite, given his contempt for him?

Answer 1

First we should ask: when did Pettigrew receive the Dark Mark?

We know from Moody’s photograph that Pettigrew was part of the original Order of the Phoenix:

[Harry's] mother and father were beaming up at him, sitting on either side of a small, watery-eyed man Harry recognized at once as Wormtail: He was the one who had betrayed their whereabouts to Voldemort and so helped bring about their deaths.

— Order of the Phoenix, chapter 9 (The Woes of Mrs. Weasley)

Turning up to Order headquarters with a Dark Mark would provoke suspicion. Since Pettigrew pretended to be an Order member until the end of the war, he must have received his Dark Mark very late in proceedings. I’m guessing when he sold out Lily and James to Voldemort.

Also worth noting that Snape turned before Voldemort’s downfall, and would surely have told Dumbledore about a Death Eater among the Order ranks. (If it later emerged that he’d known and didn’t tell anybody, he’d lost everybody’s trust.) That means that Snape, one of Voldemort’s true inner circle, didn’t know Pettigrew was a Death Eater.

(However, note that Pettigrew was a spy for at least a year.)

---

Now we can answer: why did Pettigrew receive the Dark Mark?

I think it comes down to two reasons:

• He provided very valuable information about the Potters.

  Remember that Voldemort believes Harry is the only thing that can stop him, and is supremely arrogant. Once he has Harry’s location, he believes he can easily kill Harry and his parents, and then he will be invincible.

  For all his contempt for Pettigrew, that’s pivotal information. If it pans out, there will be credit for Pettigrew in the new world order. (And if Pettigrew is lying, Voldemort needs an easy way to hunt him down and kill him.)

• Pettigrew is a coward and a turncoat.

  Voldemort knows that giving up the Potters is betraying some of Pettigrew’s oldest friends. He realises that Pettigrew just runs to the biggest bully in the room, and that if the tides turned Pettigrew would happily sell him out.

  Branding him with the Dark Mark ensures his loyalty, because it marks him as a Voldemort supporter and will see him shunned by the Order. He has nowhere else to go.

  Also note that Pettigrew could alert the Order to Voldemort’s interest in the Potters. (Although Snape does this, Voldemort believes Snape to be his agent.) If he did so, the Potters could be substantially harder to kill. Better to brand him a Death Eater and keep him close.

Answer 2

Fenrir Greyback

Let's start by clearing Fenrir Greyback: Although he is an extremely valuable asset for Voldemort, the main problem is that he's a "Filthy Half-breed". Of course, this is not expressly directed at werewolves when said. However, we see throughout the series the discrimination they receive from the "normal" witch and wizard culture.

"But then Dumbledore became Headmaster, and he was sympathetic. He said that as long as we took certain precautions, there was no reason I shouldn't come to school...." (PA18)

I mean, it took Dumbledore alone to get a Werewolf into Hogwarts, which also means that Fenrir likely didn't go to school, which could be another part of his reason, but i digress.

Peter Pettigrew

I have a few theories on this, which can be separately responsible or may each have a part to play.

Theory 1

We know that Pettigrew was a wizard albeit a somewhat limited one. It is likely that Voldemort never witnessed his magical prowess or there lack of. Until the time of his resurrection, it is hard to believe that Voldemort had seen Pettigrew cast any spells at all. It is possible to believe that with Voldemorts lack of knowledge and his graciousness at Pettigrew's betrayal he gave him the Dark Mark.

Theory 2

To stop Pettigrew from being able to betray Voldemort, he (Voldemort) branded Pettigrew. There is likely one thing Pettigrew would fear more than Voldemort (at the time), and that would be Azkaban. This would help to ensure his loyalty through cowardice.

Theory 3

It seems, based on Sirius' confrontation of Pettigrew, that Voldemort either cast him aside or allowed him to return to his life in order to spy on the Order and his old friends. Now we see another possible reason which is to contact Voldemort for information.

Theory 4

Let's be honest. When you meet Pettigrew, it is incredibly obvious that he is an utter coward. It is more than likely that Voldemort gave Pettigrew the mark as a way to monitor him or to keep him safe. It is even likely that Pettigrew required the dark mark before he would snitch as a way of keeping himself safe.

Summary

On the whole, you can see that there are a lot of reasons for the the whole branding of Pettigrew. He is not pure-blood but then neither is Voldemort himself or of course Severus but this could still be an against for his branding. Other than the saturation of his death eaters I can see no other strong negatives for branding Peter. After all it serves a purpose.

If he received the mark after the first reign

Then I think it's fairly obvious that he merely used Pettigrew as a way to broadcast his return to the Death Eaters. We will have to presume that Voldemort is the only one who can give the Dark Mark, it is complicated magic. Although Barty Crouch Jr is a capable wizard and could be taught how to give the Dark Mark during his time with Voldemort around the GoF. So it is possible that he did indeed receive the mark after the first reign, this however makes the answer much shorter.

To summon the Death Eaters. He was a whatsapp group message.