Lore Details About Death Eaters The 'Harry Potter' Films Don't Tell You

Only a select few were trusted with the Dark Mark, which was less of a tattoo and more of a powerful spell. Those who had it were magically linked to one another and to Lord Voldemort. Whenever they were needed, he placed his wand on the Dark Mark and said the "morsmordre" spell, which let his followers know immediately where to go.

When Voldemort perished, the Dark Mark didn't disappear from the people who had it. Instead, it transformed into a scar, but not at first. When Voldemort was defeated the first time, the Dark Mark faded but still retained some magic. Once Harry Potter finally got rid of him, the Dark Mark became a scar devoid of magic.

You might think everyone in the Malfoy family was a member of the "organization." Lucius was decidedly evil, and even Draco joined up and received the Dark Mark. But Narcissa, Lucius's wife and Draco's mother, never officially (or unofficially) joined the group. That's not to say Narcissa didn't jive with the group's ideals, and she showed her affinity to pure-blood witches and wizards often, but she never joined. There are several theories as to why, but it was never fully explained. 

Similarly, Dolores Umbridge wasn't a member. She was more than willing to carry out evil deeds, and her beliefs certainly aligned with some of their ideals, but she never joined the group. She considered Voldemort a villain and thought her actions were good, which in many ways made her far more dangerous.

None of the wizards who followed Lord Voldemort was as valued to him as Bellatrix Lestrange, his lieutenant and most trusted ally. Voldemort didn't have friends, but Lestrange was as close to one aws he got. A member of Slytherin House, she learned the ins and outs of magic at Hogwarts School of Witchcraft and Wizardry in the 1960s.

As soon as she graduated, she became a devoted follower of Voldemort, who trained her personally in the Dark Arts. He took a particular interest in Lestrange's fanatical devotion to him and her hatred of anyone who wasn't a pureblood witch or wizard. He transformed an already powerful witch into one of the most dangerous magical users seen in a generation through his training. She served her master well, happily capturing, tormenting, and killing whomever he asked.

Lestrange took particular interest in tormenting children, including Hermione Granger, and was responsible for numerous demises. During the conflict at Hogwarts, she felled many witches and wizards. Still, when she attempted to slay Ginny Weasley, her reign came to an end via Molly Weasley's immediate and decisive spell, which decimated Lestrange where she stood.

At their core, Voldemort's followers were pure-blood supremacists who despised anyone whose blood wasn't 100% from a bloodline of witches and wizards. It was the fundamental basis of their being, but they couldn't all be purebloods. There simply weren't enough purebloods left in the world to make up their ranks, suggesting that some were half-bloods who hid that fact from the others.

Hermione explained this situation in Harry Potter and the Half-Blood Prince, saying Vodlemort's followers can’t all be pure-blood; there aren’t enough pure-blood wizards left. I expect most of them are half-bloods pretending to be pure. It’s only Muggle-borns they hate, they’d be quite happy to let you [Harry Potter] and Ron join up."

Like any wizarding family living during the time the series is set, the Weasleys underwent significant challenges and horrors as a result of the First Wizarding War. They didn't just sit it out on the sidelines; they were deeply involved in the Order of the Phoenix.

They took the fight to the bad guys, but it cost them. Molly Weasley (née Prewett) lost two of her brothers when Antonin Dolohov offed them. Dolohov was an incredibly powerful Dark Wizard, rivaling Bellatrix Lestrange and Snape in terms of power. He often tormented Muggles for fun, but spent most of his time tormenting and slaying any witches and wizards who weren't supporters of Voldemort.

Dolohov felled Gideon and Fabian Prewett during this time. He was caught and convicted of his misdeeds, resulting in his imprisonment in Azkaban. He escaped during the mass breakout in 1996 and took part in the struggle at the Department of Mysteries. He was captured and incarcerated, but escaped once more. Later, he terminated Remus Lupin and several other witches and wizards during the final conflict Hogwarts, but when he faced Filius Flitwick in a duel, he was finally defeated.

Most of Voldemort's followers appeared to be men. Whether Voldemort had trouble recruiting women or practiced some form of magical sexism isn't known. But one woman, Bellatrix Lestrange, was not only one of the most powerful Death Eaters, but also Voldemort's lieutenant.

The other known female member was Alecto Carrow, who doesn't appear much in the films. Little is known about her other than she taught Muggle Studies when Snape took over as Headmaster of Hogwarts School of Witchcraft and Wizardry.

Molly Weasley terminated Lestrange after she attempted to slay her daughter. Carrow fought against Luna Lovegood and was either slain or taken into custody.