AN: I do not own the Harry Potter franchise.
Chapter 10: Family
While the child may have thought James would incorporate physical violence into his daily routine rather than just screaming, he didn't. Sure, he continued to be verbally violent, but he never so much as slapped the smaller twin after the incident in his study.
Soon after that particular incident, the twins turned nine and the healthier twin was given his own practice wand for his tutoring. His twin, on the other hand, continued to be ignored at best and screamed at at worst.
However, with their newfound safety in the library, they were largely able to ignore their family. They had given up on some kind of reconciliation with their family and threw themselves into their books rather than dwell on just how sad their family dynamic was. They knew their family didn't want them, and while that was upsetting it also made them spend that much more time in the library looking into dusty books they should have left alone to avoid dwelling on those thoughts.
Eventually, they realized that the books they were reading were about 'dark magic', whatever that was. They assumed it had something to do with the violent, more volatile nature of the magic as opposed to the generic, soft magic they had read about before. The magic they were reading about was also something that James ranted and raved about more often than not when drunk, so reading books on it was particularly enjoyable for the smaller twin. It felt like they were insulting James whenever they chose not to avoid the darker, dustier books in the library, and they derived a great deal of joy from that.
With their new study habits and willingness to feel resentful of their 'family' and not try to make everyone except for themselves happy, they had found a way to be content while existing in the Potter household. Their supposed 'family' may not have assisted in their happiness, but they had found things that made them happy and ways to avoid things that made them unhappy. Their life was as lonely as it always had been, but it was likely the happiest it had ever been until then. James may have continued his screaming whenever he could see his 'daughter', and Lily and the vibrant, outgoing twin may have never tried to help the sickly child, but the sickly child was relatively joyful almost all of the time.
Their family had failed them, had given up on them, and the child had finally decided they could give up on their family, too. If families were supposed to be like theirs, they didn't want a family at all. They were perfectly fine on their own. In fact, they were probably doing better on their own than they had when they were trying to be a part of a family. Therefore, abandoning the concept of family was a perfectly reasonable thing to do.
The books in the library provided more comfort than their family ever had, so if they were to choose a 'family' for themselves, they would pick the books on the shelves in the place they felt safest. The sound of pages turning and their footsteps on the hardwood floors were far preferable to a screaming man, humming woman, and a vivacious child anyways. They did not want to add the sound of turning pages to rooms outside of the library and their bedroom or invite their twin or mother into the library to talk about books they had read. They were perfectly fine with just books and dust for company.
At least books didn't scream at them when they cried or talked too loudly. Which was… odd, considering they should be warded somehow in order to prevent curious nine-year-olds from finding how-to books on draining every drop of blood from a person without them passing out or dying too quickly. But oh well, there was nobody to tell them they shouldn't be learning legal variants of the cruciatus curse. There were only people ignoring them and/or screaming at them for whatever reasons they could think of.
Maybe one day they would start quoting those books on torture when James started screaming. But James might use his position in the ministry to lock them in Azkaban, which would be terrible, so maybe they wouldn't put effort into memorizing entire passages on uses for cleaning charms in torture. Once they had a way to stay out of Azkaban, though, James would most definitely hear about rituals involving rusty spoons, blind virgins, and flamethrowers.
Sometimes they considered telling Remus and Sirius what was happening, when it felt like they could throw themselves out of a third-floor window without anyone noticing, but they knew James was more likely to be believed. When their magic was bound, Sirius and Remus hadn't done anything to stop it so who's to say they wouldn't stop James from choosing everyone over his poor, sickly little 'daughter'? It was best for them to just scream in those strange new rooms that had appeared when they felt especially unimportant and unloved. Besides, for all they knew Sirius and Remus had known what was happening from the beginning.
The only family they had were the books in rooms nobody else knew about. Not James, Lily, their twin, or even Sirius and Remus were 'family' to them. There was only one reliable and constant thing in their life that didn't hurt them, and it was the library.
Their blood relatives had long ago stopped being 'family' in their eyes.