"Cissy?" Bellatrix began. Her youngest sister was lying on her lap as she ran her fingers through her long, blonde hair. "Are you alright? You seem sad today."
Narcissa had been trying to hide it, but knew she couldn't. Her gaze had been focused on the crackling flames in the fireplace as they danced around and she avoided eye contact with her sister. She did not look away as she spoke. "No. I'm not."
"What's wrong?"
The younger sister sat up and tried desperately to hold back the tears threatening to pour from her icy blue eyes. She knew she had to do this, no matter how much she didn't actually want to. "Bella, what we're doing is wrong. It always has been." As she felt her sister's thin fingers reach over to wrap around her hand, she pulled it away. "No. I can't do this anymore."
Bellatrix Lestrange, for the first time in years, had salty, sorrowful tears blur her vision, but managed to stop them from falling. "But you never cared before. You always said that it didn't matter as long as we loved each other."
"I was wrong. You're my sister, not my lover, and I should start acting like it. We're much older than we were before you went away to Azkaban, and we should know better by now. I'm married, Bella, and have a son! You're married too." The usually gentle sister's demeanor suddenly switched from melancholy to angry. "Besides, now I've seen how you are with the dark lord. You follow him like a lovesick puppy and I really don't get why."
"That's why? You're jealous of him? Cissy, I love you. I don't love him."
Narcissa quickly stood up, her heated rage finally melting her icy eyes and forcing what she had been suppressing to be released. "Don't lie to me! I know you do! Why else would you be putting your life on the line for him time and time again and are even going into a full on war for him?!"
Bella stood up as well, following her sister's unexpected outburst. She would not be overshadowed by someone so much weaker than herself, even if it was her own sister. "Excuse me for fighting for a cause I believe in! I didn't think I needed your okay to help protect blood purity!"
The younger sister could see the rage building in the dark eyes that stared straight at her. She didn't think Bella would ever hurt her, but she'd also never seen her this angry at her before. She could still see the immense pain hiding behind it, however, and realized just how much she'd truly hurt her. Silence remained for a few moments until she finally spoke again. "Leave, Bella. Her voice was quiet and trembled as badly as her body was. "Get out of my home now."
Bella's heart sunk into her stomach and she could think of nothing to say. Her anger and madness took over and she slapped the other woman with as much force as she could muster, knocking her face down to the ground. "I'll leave, alright, and I won't come back." She pulled out her wand and aimed it at the fragile creature lying on the floor before her, in tears and gripping her throbbing cheek. What small shred of sanity the darker witch had, which, despite popular belief, did exist, was killed when she lost the one person she had ever allowed herself to truly love. Her mind became nothing more than a toy to her madness and she willingly gave it full control.
"Bella, please, I didn't-"
"Shut it, Narcissa!" Bella snapped, interrupting her sister. "Don't expect me to be a nice, helpful big sister anymore! If you speak a single word to me that isn't absolutely necessary, I WILL make you regret it!" She hissed. A familiar word followed, then a red flash of light shot out of her wand and hit the already pale and frightened woman on the floor. In a fit of angry, sadistic pleasure, Bella's lips curved into a slight smile at the sight of her sister writhing and twitching on the ground in unimaginable pain. Her cries and shrieks reached only deaf ears that no longer cared about her pleading for mercy.
When she was finally released, Narcissa turned her gaze up to her sister's dark eyes and knew there was nothing left of the woman she loved. She also knew it was all her fault. She knew Bella's mind constantly teetered on the edge of complete and total madness, but she had still given her that final push over the edge. The Bellatrix she knew, that she had given her heart to, that had been her everything, would never return. As Bella walked out of the room, leaving Narcissa completely alone, she knew she didn't need any sort of torture or spells to regret what she had done. Losing her forever and seeing that look in her eyes was more than enough punishment.
Tears fell onto the face of Bellatrix Lestrange's lifeless body, killer earlier that very same day, not long before. They came from the eyes of her younger sister, who knealed by her and, despite a few prying eyes, held her cold hand tightly in her own, gently massaging it with her thumb. "I'm sorry, my darling," she whispered, making sure no one could hear what she said. "I wish I could have made your last days happier instead of ruining them. Please forgive me. I do still love you and I always have." She let go of the hand she held and set it gently down. "Goodbye, Bella."
Having said her final goodbye, her heart aching like it never had before, and her mind full of regrets and what ifs, the youngest Black sister left that battle field with tears streaming down her cheeks. Lucius and Draco were waiting for her, just out of earshot. Once she began walking away from her sister, Lucius approached her. "Are you alright?"
Narcissa's lips curved into a feigned smile. "I'll be fine." She couldn't tell him why she was so upset. Yes, losing a sister would be upsetting, but losing both your sister and your love at once was almost more than she could handle. Still she had to stay strong, for her pride wouldn't let her do otherwise. She would have to hide the true extent of her pain, her grief, her emptiness, and her immense guilt, because Bellatrix and the relationship they shared had to forever remain her little secret.