Demiourgos (デミウルゴス Demiurugosu, lit. Creator in Greek) is Kukuri Tachibana's guardian angel and the very manifestation of her soul.
Demiourgos is depicted as a slender female angel with bleached skin. Her pale blond hair, which is even longer than her own height, floats unnaturally to two sides behind her, giving the impression of an extra pair of wings. She has a total of 14 visible eyes: two normal eyes, one in each palm, four on each thigh and two down her belly; all of them are red and none has pupils. There are four halos accompany her: one above her head and three more behind her back. Each pair of her wings are located on her elbows. In addition, her toes are unusually long.
As Abraxas, she only has one pair of wings, one halo above her head and her hair is more natural. Her eyes and mouth are sealed shut while her arms and legs are severely restricted, giving her the aura of a condemned angel.
After the battle between the Punishment Squad and Lieselotte Werckmeister on Ayame Hill in 1945, fragments of the VoidStone, the source of Lieselotte's power was scattered across six parallel dimensions. They automatically embedded themselves into the bodies of six protagonists of Sin, Damnation and the Atonement Girl arc and gave each of them special abilities from Lieselotte. The fragment in the body of Kukuri gave her the power of Soul Manifestation and created in her body Demiourgos, the angel of light. After her brother's death however, Kukuri tried to seal her memories away, resulting her loss of voice and memories while Demiourgos was reduced into a weaker form called Abraxas (アブラクサス Aburasakkusu). The amnesiac Kukuri thought Abraxas was her true power all along and fought in the Red Night with its power, until Yuka Minase's power awakened and broke the seal on Abraxas.
As Yuka tried to use Phantasmagoria to create a perfect world where only she and the one she loved, Kakeru Satsuki, knew each other, she inadvertently broke the seal on Abraxas and awakened both Kukuri's lost memories and her power of Demiourgos. Kukuri kept this fact a secret, but wasn't afraid to show her true power in the final battle again a transformed Avaritia. After the battle, Kukuri used Demiourgos's power to kill Shiori Momono and destroy the Fragment inside her. She did the same with Misuzu Kusakabe and, finally, herself. After regenerating, she went on to absorb Kakeru's Eye of Aeon to save him from being killed by the Eye. The Eye then gave Demiourgos a tremendous boost of power.
With her new power, Kukuri recreated the world by wishing that her friends would survive the battle, but would not remember anything about her since someone who held the power of a god could never exist in the same dimension as normal humans. Her wish came true; however, she realized that a part of her still wanted to be with Kakeru and refused to be separated from him. Realizing that was not the end of her wish, Kukuri allowed her heart to live as a human being while the other part would live as the god Demiourgos. The human Kukuri was surprised and asked if Demiourgos, or the other her, always had her own consciousness all along. Demiourgos denied and said that her consciousness was given through the absorption of the Eye of Aeon, which contained the souls and wishes of everyone it saw. As Kukuri was amazed by the miracle, Demiourgos added that a part of this happened also because she wanted Kukuri to be happy.
Saying that she would be always watching her from the above, Demiourgos then bid Kukuri farewell and disappeared.
- Chain attacks: Demiourgos's basic power is sending out bladed chains to impale or restrict the enemy's movement. In her Abraxas form, the chains mysteriously come out from behind her back, while her original form sends them directly from her hands. Few people know that the blades at the top of the chains are also the core of Demiourgos; should the chains take damage, Kukuri's soul will also take serious injuries.
- Aether manipulation: While not chained, Demiourgos has the ability to manipulate Aether at will, which manifests in the form of generating objects and healing, and also in destroying anything that can be affected by Aether. In the battle against Avaritia, she was able to copy the crystal used to imprison Lieselotte to make a shield for Shiori. This power is further strengthened after Demiourgos absorbed the Eye of Aeon, which enabled her to create new realities.
- Regeneration: Abraxas has a powerful healing power, capable of healing even the most serious wound. It is later revealed that this power originates from Demiourgos's regeneration ability. This ability functions similar to Yukiko Hirohara's power, except it can also help others regenerate. In addition, Demiourgos's regeneration is of a greater level compared to Yukiko's.
- Eye of Precognition: Demiourgos's right eye functions the same as Kakeru's Eye of Aeon.
- Eye of Reminiscence: Her left eye can peak into the past of anyone she desires to see.
- In the anime, only Abraxas made an appearance and it already has a conscious as Kukuri didn't control it anymore after she killed both Kakeru and herself.