The RBC series, by Murkybluematter, on FF.net.
The Pureblood Pretense, Book #1: ”Harriett Potter dreams of going to Hogwarts, but in an AU where the school only accepts purebloods, the only way to reach her goal is to switch places with her pureblood cousin. The only problem? Her cousin is a boy. Alanna the Lioness take on HP.” COMPLETED. https://m.fanfiction.net/s/7613196/1/The-Pureblood-Pretense
The Serpentine Subterfuge, Book #2: ”Harriett Potter survived her first year masquerading as a pureblooded boy, but sinister forces are now moving through the wizarding world, and when something sinister starts moving through Hogwarts as well, Harry and her friends are pulled into another maelstrom, whether Harry likes it or not. Book two. Alanna the Lioness take on HP.” COMPLETED. https://m.fanfiction.net/s/8239413/1/The-Serpentine-Subterfuge
The Ambiguous Artifice, Book #3: ”Harriet Potter's third year masquerading as a pureblood boy promises to be even more complicated than the last two. All she wants is to get through her studies unimpeded, but with pureblood politics, ancient artifacts, and adolescent hormones getting in the way... well, at least she's up to the challenge. Alanna the Lioness take on HP, book three.” COMPLETED. https://m.fanfiction.net/s/10041727/1/The-Ambiguous-Artifice
The Futile Facade, Book #4: ”Harriet Potter is back for a fourth year of quietly masquerading as her pureblooded cousin in order to pursue her dream. There are those in the Wizarding World who refuse to see her fade into the background, however, and when the forces she's been ignoring conspire to bring her to the fore, it will take everything she has to see her artifice through. Alanna the Lioness take on HP4.” COMPLETED. https://m.fanfiction.net/s/11911497/1/The-Futile-Facade
The Malignant Masquerade, Book #5: ”Harry thought she was done, but the ruse wouldn't let go. Four years of lies could not be erased overnight, and there were lies beneath the lies... As Harry tries to find normalcy and mend bridges, the Ministry trails her, Riddle hunts her, Voldemort haunts her, and her friends race toward Rigel's identity, certain he will need help before all is finished. Book 5, SOTL take on HP.” STILL IN THE WORKS. https://m.fanfiction.net/s/13903152/1/The-Malignant-Masquerade
It’s iconic, unforgettable, focused and detailed, engaging and engrossing. You know it’s the real deal when people are writing fanfiction of another fanfiction. Anything you could ever want from an HP fanfiction.