Cinderella's Brother

One day, a half-sister suddenly appeared. Because of her presence, his father became a fool and his older brother became a siscon. Having become a non-existent member of his family, he went to the battlefield with honor, but in the end, he met a bitter death. But when he opened his eyes again, he had returned to the past when he was thirteen.

However...

"I'm a eunuch... ''

Not as a man, but as a woman?

(Source: CL Production, translated)