We actually know very little about Bellatrix apart from what we can piece together. Born Bellatrix Black, she was cousin to the rather popular Sirius Black. She came from a well-off pure blood family and had two sisters, Andromeda and Narcissa. We can gather that Bellatrix is a few years older than Sirius, but that they went to the same school, as Severus Snape hung around with Bellatrix and her other friends. So, again, we can assume that she was in Slytherin House.

During her school years, it seems clear that Bellatrix had a talent in the Dark Arts and was quickly snatched up by Voldemort to join his Death Eaters. It is possible that she spent summers between school years in training with him for the Dark Arts. In any case she is one of Voldemort's inner-circle (quite unusual considering she is a woman).

Some time after school was completed, Bellatrix married Rodolphus Lestrange. They cannot have been married too long before the Wizarding world got caught up in the War effort. When Voldemort disappeared, Bellatrix, Rodolphus, Barty Crouch and Rodolphus's brother went to find out what happened to their Master. In this effort, the group captured Auror, Frank Longbottom and his wife. Bellatrix seems to have been the head of the group and she tortured both of them using the Cruciatus Curse. They discovered nothing, but it seems that they were captured shortly after.

After their capture, the group were taken before the Wizengamot for judgement and were unanimously given life-sentences in Azkaban. During the trial, While the other three stayed silent, Bellatrix proclaimed to all:

The Dark Lord will rise again, Crouch! Throw us in Azkanan, and we will wait! He will rise again and will come for us, he will reward us beyond any of his supporters! We alone were faithful! We alone tried to find him!

During the 14 years that Bellatrix and the rest of the group were kept prisoners in Azkaban, Harry Potter, the boy who defeated Voldemort all those years ago had re-entered the Wizarding world and was now attending Hogwarts School of Witchcraft and Wizardry. Voldemort, although defeated and left as nothing but a shadow of his former self, was slowly growing stronger with the aid of Peter Pettigrew and was planning his "re-birth" into the world.

At the end of Harry's 4th year at Hogwarts, Voldemort had managed to grow strong enough to rally his Death Eaters who had not been sent to Azkaban, and with their support and he finally achieved his "re-birth". Although Voldemort had returned to power, the Ministry of Magic still denyed this was possible and so focused their efforts instead on finding Sirius Black. Only a small group of Wizard's saw fit to rally an army in order to fight the Death Eaters. Called the Order Of The Phoenix and led by Dumbledore, the secret organisation was keeping a close watch on the Death Eaters and any new developments in that field.

During Harry's 5th year at Hogwarts, a large group of Death Eaters (including Bellatrix) managed to escape Azkaban prison and return to their former posts with Voldemort. In the hunt for the Prophecy - in which Voldemort hoped he would find the secret to finally killing Harry - the Death Eaters lured Harry and his friends into the Ministry of Magic. In an effort to obtain the Prophecy, Bellatrix has several violent and non-violent confrontations with Harry and his friends. At the conclusion of one of these confrontations, several members of the Order Of The Phoenix enterd the Ministry in order to save Harry.

Bellatrix shows her true ability with magic during this time as she managed to badly maim both Nymphadora Tonks and Kingsley Shacklebolt, as well as (infamously) killing Sirius Black. She also managed to evade Dumbledore and escape the Department of Mysteries in order to return to Voldemort. Harry, outraged at the killing of his godfather, chased her and they had several more confrontations until he finally told her that during the fighting in the Department of Mysteries, he dropped the Prophecy. At this, Voldemort appeared, determined to kill Harry once and for all. Dumbledore, however, quickly came to Harry's rescue and the two powers battled until Voldemort finally retreated, taking Bellatrix with him.

- Adia