Narcissa Black and Lucius Malfoy as teenagers (In his years at Hogwarts)
Bellatrix has always been a little not alright, but never anything too severe. Most would say she was a bully, but so was Sirius based on whatever stories she heard about him in passing.
Bellatrix didn't get along well with Sirius, but she hoped he would clean himself up soon. He would deny it, but they were very much alike. He could be rehabilitated.
However, that started to change once Andromeda was burnt off. All for that muggle. Bellatrix hoped it was worth it, for Andros' sake. Sirius was burnt off in a blink, and Bella could do nothing but focus on herself.
Then Regulus died. This time it was different. Regulus was her dearest, and most precious baby cousin. Gone just like that.
If Bellatrix didn't get to have her loved ones, then neither did mudbloods. That included anyone that supported them.
Andromeda couldn't stand crazies. If she stayed in this family any longer she would become it.
The constant comparisons. The high expectations. The fake smiles, and high alertness.
She hated it. She could never trust anyone, knowing they were after something. If one couldn't go to Bella, they'd go to Andro. She was the backup plan, and always the backup. 2nd in command. Should anything happen to Bellatrix, Andromeda knew what to do.
Backhanded compliments. Gossiping behind her back. The hateful obsession with muggles. Mudbloods have never done anything to her, so there was no need to hunt them.
Ted wasn't just any old Hufflepuff. If that had truly been the case, she would've married a bloody Macmillan. Ted's kindness was influenced by his survival mode.
His kindness was always genuine, but his eyes were watchful, patient of any slight of hand. A peaceful life would be nice. So nice. She really could just disappear.
Narcissa absolutely had to be seen. She wanted to shine bright too. Unfortunately, she was her mother's daughter. Birthed for her mother to dote on, while Bellatrix and Andromeda were raised to be the perfect heiress'. Narcissa couldn't be the same, but she would show everyone that she was perfect. She would prove it. And prove it she did. She chose her husband wisely, and she played her cards correctly.
Narcissa Black is a clueless blonde? So be it. She would teach others to never underestimate her. Whether it was the personality she presented, or what was on her mind, it shall never be questioned again.
Although it was cruel, she took pride in it. While she missed her sisters dearly, it was great knowing she was the one who survived. Narcissa knew it was stupid to get the mark, and she knew the toxicity given to her was a sign of jealousy. She completed what both of them couldn't do. She handled what both of them couldn't handle.
Any influence she spread was through her husband. Her dearest lover and tool.
This time when family or anyone of importance saw her, there was hope. Admiration. She was seen and not heard, just the way that she liked it.