Different Lives, Separate Hells Book 1: Origins (REWRITE)

The Fates and their mother Ananke are cruel mistresses. They had given Izuku a cruel and unfortunate fate. Even as a young child his life was nothing to envy, being treated as a slave by his own mother and stepfather. He learned that life only brings misery the longer you live at a young age. All because of the misfortune brought upon him from being born a demigod with the fate of the world in his hands. As such he envied everyone with a better life them him. For example, his twin sister, Izumi Yagi. Everything and I mean everything he had ever wanted she had been given on a silver platter. She didn't know pain, she didn't struggle, she had a quirk. All she knew was a life filled with comfort and unconditional love while he experienced hell in every sense of the word. While she was trained as a hero he was trained as an assassin by the most wanted group in the world. She had everything Izuku ever and continues to desire. Except for her brainless mind. They say too much power makes you brainless, but Izuku would find out that it was only if you relied on it.
He had soon found out he had power greater and more versatile than his sister. However, he knew he didn't need it. After all, with his mind, who needs the amount of power he wields. Some may say he is a genius, and he is, but who said even a genius didn't struggle for their position. Who said they didn't suffer the most? Who said they didn't struggle for the power...for the knowledge they wield? Whoever did is wrong, because those geniuses and their lives would drive the average being insane with grief, paranoia, or simply just insanity.
This is the story of one such genius.