Hades (冥王ハーデス, Meiō Hādesu?) is the god of the Underworld and Athena's eternal nemesis. He chooses the man with the purest soul on Earth as a corporal vessel every time he reincarnates. His soul was born in the Lost Canvas era from Pandora's mother. Alone (アローン, Arōn?) is a young painter and also Hades' chosen body for his incarnation in the 18th century, as he possesses the purest soul in that era. He is an Italian orphan raised alongside Sasha and Tenma, who later become arch-enemies. Alone believes that everybody has a good side and disapproves the use of violence. At first he rejects his fate as the god of the Underworld, but is later convinced by Hypnos, and sealed by Pandora's kiss. Before Tenma leaves for the Sanctuary, they make a promise that, while Tenma tries to become a Saint of Athena, Alone too must try to become a good artist so that he can finish the painting of Tenma when they once again reunite.
During the next two years, his personality undergoes a drastic change after realizing everything he painted dies. Convinced by Hypnos, he starts to believe that death is the ultimate salvation. And to bring salvation to the entire world, Alone starts to paint the "Lost Canvas", a painting of the Earth viewed from space, so that after he finishes it, the entire world will die.
It has been implied that Alone is not yet totally possessed by Hades as Alone drew in the Lost Canvas an image of Tenma, Sasha and himself in their childhood. After seeing this, Pandora uses a seal given by Hypnos and Thanatos to seal him in a dimensional isolation, in hope that he will continue painting the Lost Canvas without distractions, and to keep him away from the grasp of anyone from his childhood life.
Alone confesses to Pandora that he was never possessed by Hades and that he truly believes in death as the ultimate salvation, hence he inflicts it on those he holds dear, to spare them the suffering of pain, wars and poverty, and to achieve such goals, he will use all the power of the god of the Underworld. Alone states that once the Stellar Clock (星時計, Hoshidokei?), which is visible in the nightsky, completes one cycle, the Lost Canvas will be finished, bringing death to the entire world. As the Holy War nears its climax, Alone encounters Tenma face to face, and after a bloody battle, Alone regains his former self, and feeling uneasy, begs Tenma to destroy his body to prevent the calamity that nears. As Tenma is unable to oblige, Alone is overwhelmed by the will of the god Hades, who takes completely over his body, and manifests himself wholly. Alone's features and hair transform to match those of Hades' true body, which rests in Elysion since the ages of myth, and the power of the god of the Underworld finally reveals itself in all its splendor. Hades is forced to retreat and abandons Alone's body, and flees, later encountering Tenma, Alone and Athena, who manage to banish him from the earthly plane with a combined effort. Alone's life comes then to an en