Might write more chapters, see how it goes.
Bellatrix lay in her bed exhausted; she eyed her baby daughter coldly. Her daughter lay in a black iron cot beside the bed. Narcissa sat in an armchair next to the bed talking to her sister kindly. Narcissa seemed more enamoured with her niece than her sister was. The baby fussed and Narcissa picked her up cradling her "Ugh will it be quiet" Bellatrix complained.
"She's hungry Bella" Narcissa told her sister.
"She can wait" Bellatrix refused to hold her daughter.
Bellatrix had gone through a long and hard labour to be presented with a daughter. She had hoped for a son, a son to serve the Dark Lord. He had been pleased when she promised him a son; she dreaded telling him she had given birth to a girl. The Dark Lord had pulled her out of service when she was 7 months pregnant, when she could no longer move quickly or cast spells without her stomach getting in the way. So he had suggested she went home and prepared for her hoped for son.
"Bella, don't be disappointed" Narcissa comforted her sister while rocking her niece.
"I'm not disappointed" Bella insisted.
"Then hold her, she is your daughter. Your first born" Narcissa smiled sympathetically.
"I shall have a son soon" Bellatrix said declared.
"You found it hard enough to have her, don't get your hopes up" Narcissa said quietly.
"You think I cannot have a son?!" Bellatrix almost shrieked.
"You're tiered just rest" Narcissa calmed her sister. The bedroom door opened and Rodolpus came in with the Dark Lord "My Lord" Narcissa leapt up and bowed as best she could holding a baby. Bellatrix sat up straighter against her pillows "Sit down Narcissa" the Dark Lord commanded. Narcissa sat down her head low. "Bella, I hear some congratulations are in order" the Dark Lord said smoothly.
"Yes my lord with have a healthy child" Rodolphus said coming to sit on the other side of the bed from Narcissa and the Dark Lord.
"So is your son strong and healthy?" the Dark Lord asked,
"I birthed a daughter, my lord" Bellatrix said quietly her head bowed.
"A son next time I am sure, Bella" the Dark Lord told her. Bella's cheeks flushed with colour and her eyes brimmed with tear. "Hold her up Narcissa, let me see the child" the Dark Lord commanded. Narcissa held the child up so he could see the girl's face. Her features were miniatures of her mother and already dark hair could be seen "She has your looks Bellatrix" the Dark Lord observed. Bellatrix felt a wave of pride. "And what will you do when Aurors come?" the Dark Lord asked.
"They'll will not come, my lord, we will win this war" Bellatrix announced.
"I thank for you belief" the Dark Lord smiled "I expect you to be fighting again next week"
"My lord?" Rodolphus asked confused.
"I expect Bellatrix to be back in my ranks in a matter of days" the Dark Lord clarified.
"She cannot my lord" Narcissa spoke out, the Dark Lord looked at her urging her to carry on "It's tradition for a pure blooded witch to stay in her bed for some weeks while a female relative, a sister, looks after her child. Only mudbloods and lower witches care for their own child in the first few weeks"
"I see Narcissa" the Dark Lord said slowly "Did Bella care for her younger sister when she gave birth?"
"No, my lord" Bellatrix said strongly "I have not set eyes on Andromeda since she married filth, neither has Narcissa" the Dark Lord nodded "Very well Bella you follow tradition but I see no reason to as you have only birthed a girl"
"A girl can be valuable, my lord" Narcissa said.
"Enlighten me" the Dark Lord raised an eyebrow.
"She may be married to pure bloods and carry on the pure blood race. Without pure blood girls, you would have no pure blood at all" Narcissa said wisely.
"Very good" the Dark Lord agreed "And what will you name her Bella?"
"Lyra my lord" Rodolphus answered "It's a tradition of Bellatrix's family to name the children after star constellations"
"Lyra" the Dark Lord tested the name "Very well. When will you have children Narcissa?"
"When Lucius wishes to have them" Narcissa answered. The Dark Lord laughed "A fine answer" he stood up and left Rodolphus hurried after him "Lyra Lestrange" Narcissa smiled.
"Lyra Black" Bella insisted "But Rodolphus will make her be Lestrange"
Please please review and I'll write more chapters if you want.