Azure

Azure was a powerful being and the sister of Swarm, who was the Doctor's archenemy during their forgotten lifetimes as an operative of the Division.

Biography
While her brother Swarm was captured and imprisoned by the Division in a containment chamber, Azure hid herself within a human unaware of her true nature, Anna. After eons of confinement, Swarm escaped and travelled to the house in the Arctic where Anna and her partner Jòn now resided. After destroying Jòn, Swarm brushed a finger against Anna, causing the human disguise to burn away, revealing Azure.

Now freed and active once more, Azure made her way to Liverpool where she took over a large, gothic house. As Diane was walking past the house, Azure psychically called to her, telling her to get inside the house; when Diane refused, Azure remotely forced her to walk forward against her will, dragging her into the darkened, flooded house where she revealed herself to Diane, telling her that she and her brother were "going to have fun with [her]". (TV: The Halloween Apocalypse)

Appearance and clothing
Like her brother in his renewed incarnation, Azure dressed in intricate, embroidered clothing. She had light blue skin with gold and darker-blue accents, bright blue eyes, and visible sharp teeth. (TV: The Halloween Apocalypse)