Umbrella Academy

You see everyone knows of the seven Umbrella Academy kids right? But what if I told you there was eight? You wouldn't believe me right, because no matter who you asked at the academy it was just the seven of them. But this is in fact false, you see Reginald Hargreeves in fact managed to get eight kids, not seven. Except this mysterious eighth kid was kept separate, isolated. Never once did she see or know of the other kids in the house and viceversa. When Reginald was "busy" and couldn't care for his kids, he wasn't necessarily lying. He just didn't have time for those kids. Whenever their father would seemingly disappeared he was still in the house, but he was just with the eighth kid. This eighth kid bared the name. (Y/N).