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. Like Swarm, she could reduce living things to ash with a touch as well as teleport herself across space and time at will. Swarm noted that "Swarm" and "Azure" were only translations of their actual names, albeit serviceable ones.

Biography
At some point, Azure and her brother Swarm attempted to harm the Mouri in the Temple of Atropos on the planet of Time. They were unsuccessful, and were officially banned from the Temple thereafter, with the Inner Temple and its Mouri being quantum-locked against them in fear of their return. (TV: War of the Sontarans)

While her brother 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)

Swarm, Azure and Passenger transported themselves to the Temple of Atropos, where Azure destroyed the first of the two Priest Triangles. The three came across Yasmin Khan and Inston-Vee Vinder, who fruitlessly attempted to shoot first Swarm, then Azure herself, with the two taking childlike glee in teleporting across the room to avoid his blaster-fire. She witnessed Swarm's preparations to turn Yaz and Vinder into temorary Mouri and the arrival of the Thirteenth Doctor, her TARDIS and Dan Lewis to the Temple, with Swarm giving her the responsibility of incanting the countdown to him clicking his fingers and unleashing the "full force of Time" onto the bound Yaz and Vinder. (TV: War of the Sontarans)

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)