Error in the Blood

The script said there was only one.

Hermione Jean Granger was the daughter the world expected: brilliant, brave, and destined for Gryffindor gold. But the universe has a way of stuttering. Born thirty-two days before his sister due to a rare medical anomaly known as superfetation, Castor Granger is the variable no one saw coming.

While Hermione is the Mind of the Golden Trio, Castor is the Architect of the Dungeons. A Muggle-born sorted into the pit of snakes, he is a living "Error in the Blood" who refuses to be deleted. He doesn't just learn magic; he hacks the system, seeing the logical code beneath every incantation and the social gears behind every pureblood feud.

When the Sorcerer's Stone becomes the prize in a deadly game of chess, the twins find themselves on opposite sides of the Great Hall-but never on opposite sides of the war. Between a Boy-Who-Lived with a fractured identity, a Weasley King who is more than a sidekick, and a Malfoy Prince whose world is glitching, Castor must navigate a house that hates his blood to protect the sister who shares it.

The story you know is a lie. The glitch is the only thing that's real.

(I am in no way, shape or form related to J.K Rowling nor do I support her beliefs, but her books are good.)