While Lord Voldemort was a competent villain throughout the Harry Potter series, he often required the help of his Death Eaters in order to carry out his evil schemes. Some were successful, managing to please the Dark Lord amid their battle to take over the wizarding world, but others would often incur his wrath. Some fell so far down in Tom Riddle's estimations that he would lose patience with them altogether, brutally murdering or punishing them like he would with so many of his other victims.
We now look at the best and worst Death Eaters who served under Voldemort, factoring both their commitment to the cause and their success ratio into our decisions.
Best: Bellatrix Lestrange
Of all the Death Eaters who serve Voldemort unflinchingly, Bellatrix Lestrange is the one most besotted by the Dark Lord. With her family believing muggles to be nothing, and that wizards and witches should rule the world with nothing to stand in their way, she was enchanted by the idea and decided her place all her faith in carrying out Voldemort's evil plans.
During the first wizarding war she is thrown in Azkaban for the tortures of Frank and Alice Longbottom. And, during the second, she murders Sirius Black, leads an attack on the Ministry of Magic and acts as Voldemort's right-hand man during the Battle of Hogwarts. In the play, Harry Potter and the Cursed Child, it emerges that she and Tom Riddle even brought a child into the world together while shacked out at Malfoy Manor.
Best: Barty Crouch Jr
The closest thing to Bellatrix in terms of loving Voldemort and giving him everything is Barty Crouch Jr. In the books, it's established that he started to serve the Dark Lord while still a teenager and, like Bellatrix, he was always punished for torturing the Longbottoms. Thanks to his father Barty Crouch Jr, his mother, and a house elf named Winky, however, he's able to escape.
Crouch Jr spends years under the control of his father via the Imperius Curse but begins to fight it and, when he finally breaks free, he regroups with Voldemort. He then proceeds to impersonate Mad-Eye Moody and makes sure Harry Potter wins the Triwizard Tournament so he can face off against Tom Riddle in the graveyard of Little Hangleton. Once Harry gets away, Crouch Jr attempts to murder him but is stopped and ultimately subjected to the Dementors Kiss, meaning he spent the rest of his years without a soul.
Worst: Severus Snape
On the face of things, Severus Snape was a very good Death Eater and servant to Lord Voldemort. His information helped the Dark Lord come to the decision to murder Harry, Lily, and James Potter while it was he who carried out the killing of Albus Dumbledore on top of the Astronomy Tower during the Half Blood Prince.
But Snape is a bad Death Eater because, the minute Voldemort started hunting the Potters, he changed sides to work alongside the Order of the Phoenix in their fight against both Voldemort and his Drath Eaters. We only learn this late in the Deathly Hallows, when Harry watches the life of his old Hogwarts Potion Master flash before his eyes. Snape's murder of Dumbledore was a ruse, something the two men had planned together in order to save the soul of Draco Malfoy. And his death helps Harry conquer the villain as well.
Best: Lucius Malfoy
While Lucius Malfoy does change sides late in the day, or at least backs off a little from Lord Voldemort, he's a truly good Death Eater because, for the most part, he carries out his master's orders with minimal fuss.
Lucius takes it upon himself to place Tom Riddle's old Hogwarts diary into Ginny Weasley's cauldron in the Chamber of Secrets, watching on with glee as the beast of Salazar Slytherin attacks muggle-borns within the school. Two years later he spearheads the torturing of Muggles at the Quidditch World Cup and is one of the first to arrive at the graveyard of Little Hangleton when Voldemort returns. In the Order of the Phoenix he is the ringleader as the Death Eaters try and secure the prophecy their master craves and, only when he fails, does his faith begin to wane.
Worst: Peter Pettigrew
Like Snape, Peter Pettigrew is another who has his uses for the Dark Lord. It is he who convinces Sirius Black into making him the Potters' Secret Keeper instead and, after using his manipulative traits, proceeds to relay the crucial information onto Voldemort. He frames Sirius after murdering nearby Muggles when confronted on the night of the Potters' deaths and teams up with his master again in the Goblet of Fire, playing a crucial role in the villain's shocking return.
But he sided with Voldemort out of fear, rather than loyalty. Knowing this, the Dark Lord takes steps to ensure he would pay for any acts of treachery by giving him a bewitched silver hand. Pettigrew doesn't disappoint and dies when he helps Harry and Ron Weasley escape the cellar of Malfoy Malfoy, with the hand choking him against his will.
Best: Fenrir Greyback
Fenrir Greyback is the werewolf who bit Remus Lupin, consigning him to a lifetime of misery and difficulties. And he starts working for Voldemort after the Dark Lord goes public with his return in the Half Blood Prince, carrying out attacks on muggles and threatening anybody who dares oppose him.
Greyback, despite not always being happy with Voldemort, doesn't ever let his master down. He takes great pleasure in carrying out dastardly deeds, even being dubbed a wolf who 'specializes in children' in an attempt to convince youngsters to turn on both their parents and against the normal wizarding community. He gets his comeuppance in the Deathly Hallows, though, with Ron Weasley and Neville Longbottom bringing him down.
Best: Alecto and Amycus Carrow
While technically two people, siblings Alecto and Amycus Carrow both serve Voldemort with the same unwavering loyalty throughout the series - meaning we just can't split them up. The duo were forgiven by the Dark Lord for not looking for him upon his return to power and, from that moment on, have the complete backing of their master.
The Carrows are two truly evil people. Both are given teaching positions at Hogwarts, with Alecto becoming Professor of Muggle Studies, while Amycus takes up the position of Defence Against The Dark Arts teacher. They embark on a reign of terror, torturing pupils and forcing them to back Voldemort. Amycus even spits in the face of Professor Minerva McGonagall but Harry attacks him, with the two siblings later put in Azkaban for their crimes.
Worst: Regulus Black
It is with an expression of pain and anguish that Sirius Black relays the story of his brother, Regulus, to Harry in the Order of the Phoenix. He tells of a boy who was eager to impress his mother and signs up to fight alongside Voldemort during the first wizarding war, only to be murdered on the orders of the Dark Lord. We are never told a reason why at the time but, in the Deathly Hallows, the blanks are filled in.
And it emerges that Regulus, horrified at Voldemort creating Horcruxes in order to stay immortal, had embarked on a suicide mission in an attempt to destroy the locket of Salazar Slytherin, which is placed in a cave somewhere. This shows he was treacherous to the Dark Lord but his sacrifice isn't in vain. The replacement locket he places within the cave's basin leads Harry to uncovering the truth and the Boy Who Lived ultimately fights to ensure his godfather's brother's death was not in vain.
Best: Antonin Dolohov
Antonin Dolohov is a skilled wizard, one whose combat skills definitely benefit Voldemort. He fought alongside the Dark Lord in the first wizarding war, torturing muggles aplenty and participating in the murder of Order of the Phoenix members Fabian and Gideon Prewett.
When he escapes from prison, he teams up with Voldemort again. As a result, he's part of the group of Death Eaters who try and steal the prophecy from the Department of Mysteries at the Ministry of Magic and also among those who fight to the death in the Battle of Hogwarts. Dolohov tragically murders Remus Lupin but is defeated by Professor Flitwick. It's unknown whether he survived but, if he didn't, then another stint in Azkaban would have laid in wait.
Worst: Narcissa Malfoy
While Lucius Malfoy is one of the best Death Eaters at Voldemort's disposal, his wife Narcissa Malfoy must surely rank among the worst. We are properly introduced to her in the Half Blood Prince where she spends most of her time worrying about her son, Draco, rather than aiding the Dark Lord in his quest to take over the world.
Narcissa never seems to be on board with Voldemort's ideology, with Draco always her priority. And she is completely disloyal to the villain in the Deathly Hallows, lying on behalf of Harry Potter when the Boy Who Lived fakes his death in the Forbidden Forest. Her decision to side with Harry changes everything, with him ultimately revealing himself to be alive and managing to bring Voldemort down. Narcissa and the rest of the Malfoys also escape punishment at the end of the battle because of her loyalty.