Spoiler Warning: Spoilers for OoTP
Begins with Bela is 15 – 5th year at Hogwarts. I'm saying Sirius is a year older 16- 6th year at Hogwarts.
Heaven hath no rage like love to hated turned,
Nor Hell fury like that of a woman scorned.
Bella was now 15, and living up to her name. Bella – Beauty. She was a great beauty, and the boys had all noticed. All except the one she most wanted to notice. The one she knew she should least want to notice. Her cousin, Sirius.
The one Black who dared break tradition and become a Gryffindor, rather than a Slytherin. The one who was friends with Half-Bloods, and even Mud- Bloods. The Blood-Traitor. So many reasons to hate him – or love him. She admired strength, and it took great strength to defy the Black family. To defy centuries of tradition.
She wondered if she was attracted to him just because he was forbidden. Some moments she could even convince herself it was true. That it was nothing more than the attraction of the forbidden. But most of the time she admitted the truth: She'd fallen in love with Sirius. Her parents would be furious. They expected her to make an advantageous marriage to a Pure-Blood family. Perhaps the Malfroys, though it now seemed Narcissa and Lucious would make that match.
Still, what Bella wanted, Bella got. The entitlement of her family. And if she wanted Sirius, she'd get him. The Winter Ball was coming up. She could make her move then, she decided.
Sirius was surprised when Bella approached him at the Ball, and even more shocked at her request. "Dance with me, Sirius."
James was dancing with Lily, and paying Sirius no attention. Peter hadn't come to the dance. Sirius threw Remus a look, then gave a slow nod. One dance with his cousin would do no harm. And he had been wanting to talk to her. From what he'd seen she was dabbling in Dark Arts. Voldemort wasn't a real threat just yet, but if he kept growing in power he soon would be. And he wanted to make sure Bella stayed away from Voldemort and his Death Eaters. After all, she was his cousin, and as children they'd been close.
He took her hand, and led her to the dance floor.
"Bella, I'm worried about you. The Dark magic you're looking into… The friends you're making…"
"Then you be my 'friend' again. We were once very close, and can be even closer now," she offered. Subtlety had never been Bella's strong suite, so she made her advance obvious, and pressed closer to him.
"I hope you aren't hinting at what I think you are, Bella. We're cousins!"
"Since when did Sirius Black, the Marauder, care about rules?" Bellatrix taunted. "You and your friends ignore any rule that you don't like."
"This isn't about rules, Bella. This is about… blood."
"You dare talk of Blood, Sirius? You, the Blood-Traitor. Friends with Half-Bloods and even Mud-Bloods. You, who've turned your back on your own family. On your Pure-Blood heritage. Don't you speak to me of Blood, Sirius," Bella warned, her voice low and dark. "Besides, deny it all you will, Black blood flows through your veins. I know you have a darkness inside you, Sirius. Don't fight that darkness. Enjoy it. Let me show you how it can be… How we could be…"
She leaned up and captured his lips as she pressed her body into his. He was frozen in shock for a heartbeat before pushing her to arms length. He looked at her, trying to see his childhood friend. Had she really become so twisted?
"It's never going to happen. We're never going to happen. Yes, I have darkness in me. We all do. But you also have goodness inside you. Don't destroy that goodness. I want to help you, Bella. I don't want you to become a Death Eater. I want my childhood friend back."
"Then give me what I want. Be with me. We aren't children anymore."
"I can't. I won't. I care about you, Bella, but not like that. Never like that." He turned and walked away.
Bella seethed as she watched his retreating back. She'd offered him everything. Offered him herself. And he'd refused her! How dare he! He would pay. Oh, how he would pay, she vowed.
She threw herself into the Dark Arts, and made sure Sirius knew it. When Voldemort offered her a place as a Death Eater, she happily embraced it, and them lured Regulus in as well, knowing how badly seeing his little brother become a Death Eater would hurt Sirius. Everything Sirius loved, she would corrupt or destroy. When Voldemort ordered her to seduce and wed LeStrange she willingly agreed. After all, what did it matter anymore? She couldn't have the one she wanted, so what did it matter who it was the Dark Lord wanted her to bed and wed?
She laughed at the ruin of the Potter home on Halloween night as she watched Voldemort enter to kill Sirius best friend and godson, imagining Sirius face – his pain – when he found the ruin and dead bodies. When he realized it was one of his precious Marauders who'd betrayed them.
She laughed when he was thrown into Azcaban. When she was led past his cell, on the way to her own, she smiled and blew him a kiss.
As they dueled in the Department of Mysteries Bella wondered if he remembered that night so long ago, when he'd rejected her. When she'd vowed he would pay. She refused to admit the stab of pain she felt when he fell through the veil.
Revenge really was sweet, she told herself as she and the other Death Eaters Apperated away. So very, very sweet. Yet the bitterness lingered…