Dawn 5's endlessly-curious Ashlyn Oswin, who dated Graelyn Scythes in their youth, experienced her own world-crossing adventures, such as defeating “Uncle Sam” in a world of talking cats. She was eventually recruited by the Tourist to travel throughout the multiverse.
Ashlyn Oswin was a frank, emotionally direct, clever woman with a tendency to inwardsly demand from the cosmos that interesting things happen to her. (PROSE: The Forgotten Heroines of 10,000 Dawns Big Takeover!) She was bisexual like Graelyn. (PROSE: 10,000 Dawns, Go On, Toddle Along)
Ashlyn was a young woman with light brown hair, big eyes and a roundish face. Her eyes appeared to be a pinkish hue. (PROSE: The Forgotten Heroines of 10,000 Dawns Big Takeover!)
Early life with Graelyn
Ashlyn Oswin dated Graelyn Scythes in high school, while she was 17 and Graelyn 15, after Graelyn broke up with Petyr. Among their in-jokes as a couple was that they constituted “Lyn squared”, and they had custom, matching “Lyn^2” T-shirts made for that reason.
However, Ashlyn eventually broke it off — inadvertently doing so three days before Graelyn's birthday, to her dismay — because she felt that Graelyn, while putting on a show, wasn't actually invested in the relationship the way she'd want her to be. Some time later, she began to date Marilyn, which allowed her to reuse the “Lyn^2” gimmick, something which Graelyn felt to be in poor taste.
Nevertheless, they remained on good terms, with Ashlyn and Marilyn (and Ashlyn's host mom Petra) taking in Graelyn after she managed to expose her mother as abusive, until she got her emancipation. (PROSE: 10,000 Dawns)
Departing with the Tourist
Ashlyn grew up to become a school teacher. (PROSE: Go On, Toddle Along) One day, while out on a walk, Ashlyn encountered Pathway, who had, to no one's greater confusion than her own, just materialised inside a scrapheap in Dawn 5. It soon surfaced that the Tourist had escaped from the 10,000 Drafts, bringing Pathway and Miranda with her, and was intent on recruiting Ashlyn and Dawn 6's Shona Daniels to complete a team of five “Forgotten Heroines” who would be allowed by the Tourist's Black Pyramid to rampage throughout the 10,000 Dawns to get themselves noticed and remembered by the rest of Creation at long last. Ashlyn was enthusiastic about the plan, with her first idea being to travel to the universe where 10,000 Dawns was a work of fiction, and, once there, to kidnap James Wylder to force him to “write something else” — though the Tourist ended up dissuading her from going that particular route. (PROSE: The Forgotten Heroines of 10,000 Dawns Big Takeover!)
Rampage through the Dawns
Alongside the four other Forgotten Heroines, Ashlyn spread chaos throughout the 10,000 Dawns and their attendant Drafts. They went about “disrupting narratives” such as Redacted Pinorva's. (PROSE: Breaking the Narrative)
Alone with the Tourist
Ashlyn spent some time travelling along with the Tourist. They foiled a robot who had been planning to kill the Queen of England and take over the United Kingdom using a robot army, taught a death bot to kill its own kind, and “blew up the Enchanted Wood” in a deed that disturbed Ashlyn herself.
Ashlyn briefly tried to get back together with Graelyn, but their date was interrupted by the Tourist. The Tourist claimed that this was simply because she'd been “bored”, but was secretly trying to “adjust” Ashlyn's personality until she would be willing to have sex with the Tourist and to generally become her companion on a full-time basis.
After the two, at the Tourist's insistence, “helped a bank kidnap and brainwash an intelligent life form”, Ashlyn began to object to the immortality of the Tourist's adventures. She was put in charge of their next adventure by the Tourist, when they travelled to a Moon taken over by seemingly-hostile carnivorous giant spiders. Ashlyn got a sense of goodness from them, believing they were only aggressive because the Space Marines had opened fire first. However, she did let herself blow up the Moon with the bomb the Tourist had provided.
Taking over the Pyramid
She had, in truth, realised that due to the Tourist's metafictional nature, the adventures they were going through all mirrored adventures of the Doctor and Clara Oswald. The Tourist tried to tell her that it didn't matter and their stories were worth living even if they were patterned after Doctor Who, but Ashlyn retorted that she feared the way her story arc would go if she continued to live out a darker version of Clara Oswald's life, such as dying and then having to be resurrected by the Elders at the cost of being forced to live in slavery on their world, birthing time machines.
When it became clear that the Tourist was only interested in her carnally and didn't love her enough to even know her name offhand, Ashlyn pushed the Tourist out of the Pyramid and took it over. The Pyramid responded to her taking over the controls, changing its design to be less gothically brutal, though still slightly spooky.
Behind the scenes
Ashlyn Oswin was described in the series bible for The Forgotten Heroines of 10,000 Dawns as being “basically Clara Oswald, but a young woman in the 10,000 Dawns who dated Graelyn”.
Her name fits the pattern of Clara Oswald's splinters, another of whom was named “Oswin Oswald”, and she was drawn as a loose likeness of actress Jenna Louise-Coleman, who played Clara in Doctor Who. Should Auld Acquaintance Be Forgot suggested heavily, though in veiled terms to prevent copyright infringement, that the “Clara Oswald” briefly encountered by the Twelfth Doctor in Twice Upon a Time was actually Ashlyn posing as Clara, meaning that Coleman supposedly did play Ashlyn at least once in the flesh. The same story also implied that Ashlyn was indeed one of Clara's splinters, with her purpose being to help convince the Twelfth Doctor not to let himself die and to instead find the courage to regenerate into the Thirteenth Doctor.