I really like thinking about what Bellatrix, Narcissa and Andromeda were like growing up together as children. This kind of comes from that curiosity.
I obviously don't own anything. Duh. It's a fanficiton site.
So, anyway, here it is.
"Bella, stop!" Narcissa said. "I think you're hurting her."
"Sissy," Bella laughed, "Mummy said muggles don't feel pain. Not like we do." Bellatrix bent over the muggle girl. Her dark hair hung around her face in a curtain.
"I guess." Narcissa bounced on her tiptoes. "What are you doing?"
"I don't know," Bellatrix said. "I'm not trained in magic." Green sparks arced from Bellatrix's fingers and melted into the muggle's skin. The muggle seemed to be in some sort of magical sleep. Narcissa bounced more quickly. Bellatrix's natural grasp of magic made her nervous. Bellatrix 'hmm'ed and sent red sparks into the little muggle girl's skin. The muggle's eyes popped open and she screamed.
"Bella!" Narcissa reached out and tugged Bellatrix's arm. "Come on, Bella. We can't be caught!"
"Why does it matter so much to you what the muggles think?" Bella asked. She let Narcissa pull her back to the main road away from the park. "Daddy could wipe their memories, anyway."
"I don't care about them. I care that... Um... I don't want to disturb Mummy or Daddy." Narcissa slowed to a walk, like Bellatrix, who seemed in no hurry to escape the screams of the muggle girl they'd just left behind. "And Bella, it's time for... Um... Lunch, anyway, and Auntie Walburga doesn't like us to be late."
"You're silly," Bellatrix said. "But you're only seven, so that's to be expected. As long as you listen to me, other people won't think you're stupid."
"You won't be able to play with muggles next summer," Narcissa reminded Bellatrix. "You can't, after Hogwarts. Not until you're seventeen." She was still worried that her sister was going to get reckless the law and get sent to Azkaban. Playing with muggles was fine, and Mummy and Daddy even encouraged it, unless you got caught. Narcissa didn't know what would happen, but everyone said it would be bad. Probably Azkaban bad.
"Narcissa, drop it!" Bellatrix started to walk faster. Narcissa could hardly keep up with her older sister.
When they got back to 12 Grimmauld Place Aunt Walburga, as expected, was cross. Black family reunions were usually formal occasions with plenty of stiff people talking about gory things (which Bellatrix liked) ad politics (which Andromeda, Narcissa's other older sister, liked). Narcissa didn't really like anything that happened at family reunions, except maybe playing with Regulus and Sirius. They were two and three and the only people in Narcissa's family who were younger than she was and never called her a silly little girl.
"Girls," Walburga said when Bellatrix and Narcissa entered this dining room, "Where were you?"
"The park," Bellatrix said. "We lost track of the time. I most likely won't have time for parks next year."
"Give the girls some slack, Walburga," Uncle Alphard said. He winked at Narcissa. "It's one of Bellatrix's last weeks before she's an official young witch."
Bellatrix tossed her hair and went to sit between Aunt Casseopeia and a heavily pregnant Aunt Dorea. Narcissa, more easily embarrassed, crept in to sit beside her mother. On Narcissa's mother's other side, Andromeda bounced a three-year-old Sirius on her lap. Dromeda was nine and didn't like playing with muggles. She told Narcissa that she just didn't see the point.
"We were discussing you, actually, Bellatrix," Uncle Orion said. "The first of this new generation of Blacks to go to Hogwarts."
"We knew she would," Mummy said. "You had such obvious talent, Bellatrix, even as an infant."
Bella smiled primly, chewing on the steak a house-elf had put in front of her. She swallowed.
"I'll do my best to do the House of Black proud," she said. "I hope I get put in Slytherin." Most of the family nodded and muttered approvingly. Two-year-old Regulus banged his spoon on the table.
"I'm sure you will," Aunt Casseopeia said. "Your mother was Slytherin, your father was Slytherin... Everyone at this table was in Slytherin. You are set up to go straight to the top, Bellatrix." Aunt Casseopeia gave Bellatrix a rare smile.
"I trust you will live up to your expectations," Daddy said. Bellatrix nodded. Daddy raised his glass.
"To the values of the Blacks; To pure blood; To Slytherin; To my daughter, Bellatrix, who embodies everything expected of a member of the Noble House of Black!"
"To the Noble House of Black!" The table chorused.
