Not The Blackest Soul
Bellatrix Black never understood why she was put in prison. She thought that she had a good heart, she cared for her family and helped the people who needed it. She was the good sister.
Rudolphus had need help. He had been broken so many times by his horrible, horrible brother. It was an accident that they fell in love, or and accident that they gave the illusion of love. Their parents set them up after seeing how well they went together. It was a good, pure-blood match. Bella liked to think that by making her mother and father happy, she became a better person, a better daughter.
She was devoted to the men in her life, all she wanted was there happiness. Mother called her insane, saying she wasted her life - her talent - on her good-for-nothing father and useless husband. Mother was the insane one, she had loved Rudolphus when they had first gotten married, she had loved father too.
Bella supposed that it was the insults her mother dished out that made her raise the wand and deliver her first ever killing curse. There was no emotion, but she felt lighter with her mother gone. (They painted that portrait, and they stuck it to the wall permanently. It wailed whenever she walked past. No one ever knew that it was she who killed her own mother.)
After that she tried to convince Rudolphus that Rabastan was no good for him. That his own brother couldn't order him around forever, treating him like a piece of dirt. Less than that, a pile of dung.
Rudolphus never agreed with Bella, so she did it on her own, put herself in control of that bossy brother.
From then on, Rudolphus was in charge of Rabastan. That made Bella feel lighter too.
When he came into power, when he found her, Bella found another man to protect. Because they all needed protecting, a little bit of shelter from all the bad things in life. It was making her a better person, it was repenting for all those awful things her mother did.
He made her feel happy, by letting her dote on him. She called him 'My Lord' and all other sorts of power-granting names. It was the most rewarding thing she had ever done in her life - she was fighting a war to protect the ones she loved. Her and her husband were favoured, the envy of all others.
Bella was the first and only female Death Eater, because she cared on a level that no other person could. She wanted to protect. The others just wanted power.
And all she did was help a desperate man - for Lord Voldemort was a most desperate, desperate man - and she was thrown ungratefully into a tiny cell with no light and no dark. Just grey.
For years and years, Bellatrix chanted how she was not the blackest soul, she would never be the blackest soul. She wanted to protect, not gain power.
(Because she had lived her whole life in a shade of grey, helping and helping and helping, with nothing but the darkest magic and darkest thoughts.)
