No, Bellatrix Lestrange wasn't the only female Death Eater, but she and Alecto Carrow were the only two named women with the Dark Mark in the books, though unnamed female Death Eaters appeared in the movies and background lore. While Narcissa Malfoy was allied with Voldemort's circle, she was never an official, marked Death Eater herself.
There's only two named female death eaters in the books: Bellatrix and Alecto. So, the answer to your question is that nobody knows who this woman is, because she wasn't a character in the books.
Notable Death Eater characters
Delphi's cousin, Draco, had no knowledge of her existence. By the time he did discover who she was, Draco had given up believing in the same Pureblood values his parents had, and when he met Delphi, he had no affection or sympathy for her and her attempt to revive Voldemort.
However, there's no doubt that Professor McGonagall is the more capable duelist, and she would completely defeat Bellatrix Lestrange in a duel. It's important to remember the ongoing controversial statements by the creator of the Harry Potter franchise.
His reaction to Bella's death was akin to his reaction at the loss of the Cup, which was when he realised that his own immortality was jeopardised amidst war and his own death could have been near. This, to me, symbolises that after his own only Bellatrix's death had any impact on him.
It would be a close battle but Snape would win. Minerva has much more knowledge though so who knows what she knows because she's been around and work with Dumbledore for a long time and she knows everything about Hogwarts and a lot about the wizarding world. Also, she is the most powerful transfiguration user.
In 1943, Tom Riddle, the "Heir of Slytherin", opened the Chamber of Secrets to conduct a purge on Muggle-born students. This resulted in the death of Myrtle Warren, who eventually returned as a ghost. Riddle opened the Chamber again in 1993 through the use of one of his seven Horcruxes, his diary.
Voldemort found Nagini in Albania after his initial defeat, likely while he was a weak spirit possessing snakes; she was a unique, powerful snake, possibly a Maledictus (a witch with a blood curse turning her into a beast), making her an ideal companion, and he eventually made her his final Horcrux by murdering Bertha Jorkins with her present. Their connection deepened as he used her venom to sustain himself and later made her a container for his soul, ensuring their bond was profound and twisted.
Harry misinterprets Tonks's behavior to be about Sirius because that's how he was feeling. But Tonks was depressed because she'd been rejected by Lupin.
There's no single "saddest" death, as fans cite different characters, but Dobby, Sirius Black, Fred Weasley, Remus Lupin, and Snape are consistently named among the most heartbreaking due to their profound loyalty, tragic lives, or sudden, impactful losses, with Dobby's selfless sacrifice often topping lists for his pure heart and newfound freedom, and Fred's death devastating his twin George and family, notes Quora and Facebook users https://www.facebook.com/groups/309399756202202/posts/2389613828180774, and Reddit.
Alecto and her brother, Amycus, supported Lord Voldemort and became Death Eaters during the First Wizarding War. After Voldemort's downfall in 1981, they did not search for their master, believing that Voldemort was gone forever, and thus avoided imprisonment in Azkaban.
In Harry Potter, the "Three D's" are the essential principles for successful Apparition (magical teleportation): Destination, Determination, and Deliberation, taught by Ministry instructor Wilkie Twycross to avoid "splinching" (leaving body parts behind). You must firmly visualize your Destination, have the unwavering Determination to reach it, and then move with focused Deliberation, without haste, to arrive safely, notes the Harry Potter Wiki and Harry Potter Lexicon.
Deathly Hallows
Nagini, Voldemort's snake, then eats Professor Burbage's dead body. A story about her "resignation" from Hogwarts appears in the Prophet, but members of the Order of the Phoenix discount it, as they are unable to locate her anywhere after that.
Also, in every film with the Dark Mark in the sky, Death Eaters are shown Apparating inside and outside of its mouth in smoke form. This allows them to fly out of it and appear wherever it is cast, allowing them to use it as a sort of portal.
The youngest Death Eater in history, Draco Malfoy. Azkaban prisoner number 602, Draco Malfoy. Childhood bully and nephew to a witch who haunted Hermione's darkest nightmares, Draco Malfoy. Released early from prison, newly reformed Draco Malfoy.
Because some snakes could sense heat and movement in a way humans could not, Nagini was able to detect Harry and Hermione even when they were under the Cloak of Invisibility. Harry fought with Nagini, and the serpent bit him before coiling herself around Harry to hold him in place for Voldemort.
While Credence is a Dumbledore, he isn't the brother of Albus, Aberforth and Ariana. In fact, he's Aberforth's secret son! Aberforth met Credence's mother the same summer that Albus and Grindelwald met.
He trusted snape because snape had proven himself many times before. Voldemort took anyone that was magical and had his own ideas in common during his first crusade.
Harry is the heir of Gryffindor, although he had characteristics of both Slytherin (cleverness, resourcefulness, determination) and Gryffindor (bravery, honor, recklessness, chilvary). It is why Harry was able to claim the Sword of Gryffindor.
Salazar Slytherin
For many years, all was well among the four founders. Yet when shrewd Salazar Slytherin, 'from fen', suggested that only those from magical families deserved to come to Hogwarts, his three friends stood against him. Salazar Slytherin left the school.
The creator gave this unique wand the ability to sleep and to wake up again when instructed by speaking Parseltongue to it, a rare gift that gave one the ability to speak with snakes, and a trait that was passed on through Slytherin's family.
Page 394 in Harry Potter and the Prisoner of Azkaban refers to Professor Snape telling the class to turn to that page in their Defense Against the Dark Arts (DADA) textbook, which is about werewolves, a deliberate hint that the substitute teacher, Professor Lupin, is one himself, a secret Snape was trying to expose. While the specific text varies slightly by edition, it introduces the topic of werewolves as nocturnal beasts, contrasting with the Red Caps and Hinky-Punks they were learning about, to reveal Lupin's true nature.
He was born two years after his older brother James Sirius and two years before his younger sister Lily Luna. Albus was named in memory of Albus Dumbledore and Severus Snape, two former headmasters of Hogwarts School of Witchcraft and Wizardry and both great wizards that his father knew.
Most people's favorite McGonagall quote: "I've always wanted to use that spell" My favorite McGonagall quote: "And take Mr. Weasley with you, He looks too happy" And interestingly enough both are movie exclusive lines.