Tahira was a woman who suffered from mental illness and was hosted in a secluded citadel in Aleppo, in 1380. The immortal Zellin used her nightmares to create the Chagaska. The Thirteenth Doctor found her as the only person not abducted in the health facility and carried her within her TARDIS; therefore she met the Team TARDIS and travelled to the far future. (TV: Can You Hear Me?)