Carmen Yeh

 was a human of Chinese descent who was a companion of Compassion during the War in Heaven.

Biography
Carmen Yeh was the captain of an ElleryCorp shipping vessel whose only other passenger was an artificial intelligence named LEO. When the Eighth Doctor arrived on their ship six months into the journey, LEO wanted to kill him, but Carmen invited him to dinner; eventually, the Doctor discovered that ElleryCorp was using Carmen as an experiment on human sanity in isolation. LEO denied this and the Doctor left, but LEO then tried to kill Carmen because "the results [had] been corrupted." The Doctor rescued Carmen, and they began travelling together.

At some point after visiting Vancouver, she became trapped in a jail with the Sixth Doctor's companion Grant Markham. She told him her story, and they compared notes on their Doctors' personalities. Since Carmen had said she didn't like the strawberry parfait-flavoured biscuits from the TARDIS' food dispenser, after Grant returned to the Sixth Doctor's TARDIS, he hid some food inside a stasis field for her to eventually find.

Yeh's travels with the Doctor (NC: Schrödinger's Botanist) ended when she was accidentally left in Alaska in 1758. Soon after this she met Compassion, who was also left in Alaska after her companion from the Homeworld had left her. Compassion offered to "give [Yeh] a lift" while Compassion searched for her previous companion; the two travelled together for three years.

During their time together, Yeh persuaded Compassion to meet with the War King. Yeh gathered plenty of knowledge of the War in Heaven during her travels and wrote that Compassion thought the enemy was just a distraction and the true threat was from "family". Compassion later suggested that the emergence of House Lucia would be the indication of the real threat showing itself.

Yeh and Compassion were present at the assassination of R. B. Nevitz.

One of their most notable misadventures took place on the frontier in time. There, Compassion became greatly distressed upon finding the remains of the 103-form timeship "Percival"; she then confronted the War King in the middle of a state dinner. Compassion created a second pact with the War King and the head of House Mirraflex shortly before she stopped travelling with Yeh.

After leaving Compassion and settling down, Yeh wrote her (allegedly fictitious) memoir Fantastical Travels in an Infinite Universe, where she called herself "Yvette Carlton" and Compassion "Laura". (PROSE: The Book of the War)

Behind the scenes

 * "Carmen Yeh" is an anagram of "Archenemy".