The Orphanage was originally stitched together from two seperate buildings: a warehouse and an Inn. The Warehouse was built by a Lordling with lots of money and no common sense who built a big fancy warehouse in the middle of nowhere, diving it up to rent sections out to locals, before skipping town when the dept collectors came for him, because it made next to no profits whatsoever It entered an ownership dispute between the City's authorities and the (Now vanished) Lordling's family, whilst being used as a hideout for a criminal gang in the meantime. The Family got to keep it in the end, but it was no more profitable than it had been, so it ended up switching hands several times, before the last person to own it joined the faith. When he died, the faith inherited it, and they turned into a soup kitchen. Soon after, they turned the unused floors into an orphanage, partially so they had somewhere to dump the little gremlins and partially because the soup kitchen now had free labour under the thin guise of teaching the Orphans life skills, most of which consisted of cooking enormous quantities of soup.
The Inn belonged to a man with a son and a daughter, whose wife died shortly after birthing the son. The son got into frequent trouble with the law, and his relationship with his family became increasingly strained, until he was thrown out by his father after being caught stealing money from the Inn's profits. Despite the extremely minor presence of the Lord of Light at the time, the young man who showed up on their doorstep was penniless, alone, without meaning in life, and possessing a deep hatred for the only people in the world who might have cared about him. In his vulnerable state, he was easy to indoctrinate, and became one of few successful Westerosi converts at the time to the Lord of Light. Somewhere inside, he was trying to gain control over his life, mend his shattered and broken ego, and try to feel some sense of self importance after having ruined his own life, blaming his family for everything and turning his back on them. Meanwhile, back at home, the Sister's relationship with her father was straining, as she didn't want to marry and instead wanted to become a Septa instead to escape that life and her Father wanted her to marry. He only relented once his son took the path he did, as a middle finger to the son who would still come to the Inn to evangalize outside. Over time, however, the sister and Father mended their relationship, and when the Father died, he left the Inn, which would have otherwise been inherited by his son, to the Faith, as one last posthumous middle finger to his son. The Faith, delighted, converted the ~20 or so rooms of the Inn into four dorms divided by gender and age, turned the old common room into a feast hall, the old dorm in the Warehouse into a classroom, and the soup kitchen into... Well, still a soup kitchen, but now also feeding a significantly increased number of orphans. The sister ended up joining the Orphanage as a staff member and eventually the closest thing to a chief administrator that a Woman could reach, which may have been another middle finger that was requested of the faith by the deceased father, who included a sealed letter in his will the contents of which were only known to his daughter who wrote it since the Father couldn't write, and the Septon it was addressed to. The son shortly after departed the city for Essos in a fury, and was never seen on the continent again.
The current owners are a pair of twins (a brother and a sister), who grew up in the orphanage, joined the Faith once they came of age, and tried to mend the damage done by the previous operator of the Orphanage. The previous operator was a traumatised, crippled veteran of the War of the ninepenny Kings, who turned to the faith to try and deal with his mental health and guilt, but ended up being dumped in the orphanage where the other Septons didn't need to listen to his wailings and deal with his alcoholism. When the Twins came of age, they joined the Orphanage's staff, working to improve conditions for the children and try and ensure that none of the orphans would have to go through what they went through ever again. Once the old operator passed on, the Faith appointed them as joint operator. Although technically the brother is sole operator, it's an open secret that he'd be incapable of running it without his sister, and she would be incapable of running it without him. There were allegations of them being incestuous lovers at one point, but these didn't last long, being replaced with allegations of lesbianism from the Sister, which although much more convincing were never technically proven. During the sack of King's Landing, the Twins and staff barred the entrances to the warehouse before the Lannister soldiers reached the orphanage, sheltering the Orphans as well as many neighbours let in using roped in the Orphanage until the chaos had died down. This is probably the least important part of the very unimportant novel I have written about this building, but I wanted to have some peace of mind to know that I wasn't building a murderhouse-style Orphanage and that there were even slightly reasonable people running it. Maybe this was too optimistic, and I should have included some murder to keep within the spirit of ASOIAF, but uh... I haven't thought this far ahead, I'm just writing out of my ass now tbh. I'm going to stop now before this gets any more awkward.