Miríl was a teacher at the seminary on Kirith. He was Raphael's ward after his parents' deaths.
Miríl was curious about the universe beyond his world. He hoped to get answers from the Seventh Doctor before he, like all other visitors to his world, was taken to join the Panjistri at Kandasi. He showed the Doctor the official history of his people. The Doctor realised from inconsistencies in it that it was untrue. Stunned by the revelation, Miríl took the Doctor to the ruins of Kirith's previous inhabitants, only to learn that these were also fake.
Before they could decide what to do next, Raphael arrived to tell them what he and Ace had found in a Panjistri laboratory. All three were captured by Huldah. While the Doctor was taken to Kandasi Island, Raphael used Ace's nitro-9 to escape. After helping to convince Tanyel of the truth, Miríl accompanied Ace, Arun and Raphael to Kandasi Island. During the voyage there, he was killed by a giant sea creature which attacked their vessel. (PROSE: Timewyrm: Apocalypse)