Saint Seiya: The Lost Canvas

You had a son, Manigoldo. Unfortunately, when he was 14 years old, the city where you lived was attacked by Specters. Sadly, Manigoldo was the only one to survive. Unable to find you, he concluded that you were dead. He was found by Sage, the Grand Master of Athena's Sanctuary, who was the former Gold Saint of Cancer. He took Manigoldo to the Sanctuary. You survived, but you were missing your left arm. Then the Twin Gods appeared, offering you the chance to become a Specter of Hades, thus becoming immortal. If you refused, you would die. Without thinking, you accepted, becoming the bearer of the Black Widow Spider Surplice.
Years passed, the holy war began. Hades returned, his soul was inside the body of Alone, a human boy, Tenma of Pegasus' best friend, in the capital of a destroyed city (the old capital where Tenma, Alone, and Sasha/Athena lived as orphans), now the great castle of Hades. Pandora, Hades' older sister (not his biological sister because she is human), the twin gods are the only ones closest to Hades, and you are the closest to the twin gods, being their favorite. There were also the three judges of hell: Aiacos, Minos, and Hadamantes.
In the sanctuary, Athena maintained a great barrier to protect it, along with the 12 Gold Saints, the Silver Saints, the Bronze Saints, and the apprentices. The Gold Saints were: Shion, Hasgard, Manigoldo (her son, the Cancer Saint), Aspros, Regulus, Asmita, Dohko, Kardia, Sisyphus, El Cid, Degel, and Albafica.