Overview
Sosia is a great existence responsible for the Witching Hour incident at Belphegor Art Museum. It possesses the power to turn humans' fears into reality.
Shortly after Enfer became a Sinner from witnessing the emergence of BR-004, she received a mysterious piece of stone as a gift from an anonymous supporter. She described this stone as "unmarked, flawless, too perfect to be of this world” — most likely, it may be a piece of the Perishing Star. Touching it struck her with inspiration and she heard the voices of people crying out in fear. In a trance, she carved a statue and named it after the word the voices had been calling: Sosia. Following the wishes of the stone's donor, she displayed it at the Witching Hour exhibition. Enfer says that carving it felt like the statue had been in the stone all along, waiting for her to awaken it. She considers it to be her life's work and greatest masterpiece, and even after the Witching Hour, misses Sosia and considers rebuilding it.
Sosia seems to be a continuation of Parma's experiments to draw out human emotion into the physical world, making fears into reality in much the same way that Parma used Marv and Ambrosia to experiment with human happiness. Despite its origin, Sosia seems not to know anything about Parma or Black Rings, acting only to realize a twisted form of Enfer's artistic vision.
The sculpture depicts a pure white four-armed "holy woman" with a veil covering its face. The details of the statue are said to change under certain conditions and diverse into two different forms. It was called a "heavenly creation" by critics and is so breathtaking that space around it is changed, and people often become lost in it. Its aura of oppression is difficult to bear by one person alone. Other exhibits are often thought to be lost, only to later appear around Sosia.
Role
Night of Wonder
Sosia is the center of the mutation in the Witching Hour crisis. Nevertheless, unlike all of Enfer's other creations, it remained unchanged when transformation took place. This lasts until Enfer resolves to destroy it and end the Witching Hour. At that moment, the sculpture looks up, and its gaze turns Enfer into plaster. Sosia tells the Chief that Enfer was held back by her weakness and confusion, which caused her previous artwork to be imperfect and thus susceptible to the transformative effects of the Witching Hour. Sosia kills Enfer and consumes the black dahlia flower that grows from her corpse, awakening to her full power. Before she can spread the Witching Hour to the rest of the city, the Chief forces Sosia to look into Enfer's Gate of Hell. The gate summons the shadowy illusion of Enfer's own deepest fear: her father, represented by Enfer's famous sculpture, The False One. Faced with her own fear, Sosia is weakened and the Chief is able to pull Enfer back out of the damaged sculpture. Enfer absorbs what is left of Sosia and the rest of the contamination, ending the Witching Hour and awakening as an S-Class sinner.
The remnants of the white stone that Sosia was carved from are collected and sent to the Ring Research Institute, and its connection to PARMA is investigated by the 9th Agency.