Ganeida

Ganeida was a female wizard who lived in a cottage in the forest, four days' ride from Camelot, contemporary with the reign of King Arthur. She was Merlin's sister and, like him, was a hybrid, born to a human mother and demon father.

Early life
Ganeida was born to a nun and a mysterious individual who was also Merlin's father. It was said that he was a demon, although Agamya Akhtar suggested he was actually an extraterrestrial, something Merlin also hinted to Ganeida. Ganeida did not know her father growing up, with Merlin even suggesting he did not even realise his relationship with a nun had led to the birth of any offspring for many years, but she was aware that she was half-demon and "Merlin's little sister". (PROSE: A Honeycomb of Souls)

The Morch'aliach affair
During the reign of King Arthur, Merlin learned of the presence of the Morch'aliach entity near Camelot, but was unable to help with its defeat because he was invited to a party on another world. As a substitute, he directed Bedevere, Agravaine, Gawain and Galahad to Ganeida's cottage. The four Knights of the Round Table found Ganeida brewing a potion outside her cottage. They journeyed to the cave; feeling the "evil" coming off from it, Agravaine suggested they simply seal it and leave the problem to future generations. Like the other three knights, Ganeida objected, in her case in part because, having an augmented life-span due to her half-demon heritage, she would actually be there when the problem came up again. However, Agravaine ignored their advice and caused a rock slide that collapsed the entrance of the cave while the others slept.

After they returned to Camelot, a celebratory feast was organised, even if the victory was incomplete. At the celebration, Ganeida slipped away from the bulk of the festivities and found her brother lurking at the edges. The two, who had not seen each other directl in some time, reconnected, even dancing together. Merlin then sent Ganeida to the future to take care of Morch'aliach, suggesting it "might be fun" if she teamed up with the Preternatural Research Bureau to do so. Arriving in 2019 London, she headed to the address Merlin had given her, where, on top of meeting the rest of the P.R.O.B.E. team (including Giles, Azacca Dixon, Maxie Masters, Agamya Akhtar and Tasha Williams), she was, much to their mutual surprise, reunited with Sir Bedevere, now a kind of ghost drifting between time-zones due to a curse from a witch.

Together, Ganeida and P.R.O.B.E. enlisted the help of Origin Zero and found the house built on top of the location of the cave. Morch'aliach had taken over the basement and seemingly consumed the owners of the house. After Bedevere stabbed the entity with his ghostly sword, however, the wizard was able to defeat it by speaking a "story" into existence (with the help of the others), using the sword as a link to summon the souls or memories of King Arthur and his Knights to greatly weaken the entity. After it was reduced to a single wriggling worm, Ganeida crushed it underfoot. After this victory, she stayed for dinner before she returned to Camelot. (PROSE: A Honeycomb of Souls)

Later life
Although the Ganeida met by P.R.O.B.E. in 2019 was a young Ganeida from Arthurian times, who had time travelled to the 21st century with Merlin's help, Ganeida and Merlin both believed that, thanks to her half-demon parentage, Ganeida would naturally life well into the 21st century. Around the time of the Morch'aliach affair, Merlin promised to keep dropping in on her "for as long as they both would live". (PROSE: A Honeycomb of Souls)

Appearance
Ganeida had red hair, which she usually kept in a somewhat careless ponytail. Her most striking feature, marking out her half-human parantage, were her eyes; they were lynx-like and heterochromatic, with the left one being red and the other blue. Additionally, the left side of her face was nearly covered with a wine-red birthmark, which "encircled the eye and just barely touched her lip".

In her native time, she usually wore a two-layered blue outfit, with robes draped over a dress. The latter was embroidered with runes and sigils. Visiting the 21st century, however, she adopted a less conspicuous outfit including a long blue peacoat that went down to her knees, jeans, and a Daisy Struts T-shirt. She kept a variety of items in her pockets, including books, receipts, a microphone, and (somehow) a whole a coffee cup. (PROSE: A Honeycomb of Souls)

Behind the scenes
, also "Ganieda" or "Ganeida", is a figure from early forms of Arthurian myth. She was traditionally depicted as the twin sister of, rather than his half-sister as shown in A Honeycomb of Souls, although some scholars believe that the earliest references to the character actually intended for her to be Merlin's lover and a member of the Fair Folk. In Geoffrey de Monmouth's 12th-century Vita Merlini, Gwenddyd is described as being married to a nobleman,. Merlin's playful remark at the end of A Honeycomb of Souls that "a Lord" has been making eyes at her seems to be a reference to this.

Although he is not the only character to have embodied Merlin in the Doctor Who universe, it was claimed in the Doctor Who TV story Battlefield and several subsequent works that Merlin was an incarnation of the Doctor (variously claimed to be the Eighth Doctor, the Tenth Doctor or a far-future incarnation). A Honeycomb of Souls subtly alludes to this by suggesting a modern understanding of the legends of Merlin's "half-demon" parentage as his father having been of extraterrestrial origin (thus tying back to the suggestion that the Doctor is half-human on their mother's side). If one takes this interpretation of the Merlin seen in A Honeycomb of Souls, this would make Merlin and Ganeida's father Ulysses, and Ganeida herself a half-Time Lord hybrid like her sibling.