Dagmar Ruskovitch

 was the Baroness of Castle Houska in Central Bohemia in 1601. According to Tycho Brahe, she was described as being "as formidable as she [was] beautiful."

Biography
Ruskovitch organised a gathering of astronomers, mathematicians, and scientists from across the world at Castle Houska, of which Tycho Brahe was the most famous guest. He was accompanied by his then-student, Johannes Kepler, and later joined with the Thirteenth Doctor, Graham, Yaz, and Ryan to visit the gathering.

Ruskovitch was first seen practising archery in the courtyard of the castle, being informed by a monk called Olaf that neither Galileo Galilei nor John Dee would be arriving. Although angered over a plan she had, she was calmed by another monk called Dominik that a new mind for them was arriving. Once everyone had arrived at the party, she greeted the congregation. Concerned about the meeting, the Doctor introduced herself and asked why everyone at the gathering could suddenly speak each other's languages, but the question was quickly shrugged off. The Baroness later met Kepler and Yaz and invited Kepler to a private showing of her literary collection.

In her vast library, she told Kepler that he had great potential, and gave him a glowing orb that would show him new knowledge. However, this was interrupted by a furious Tycho, alongside Graham and Yaz, upon which she realised their connection to the Doctor. Upon being psychically informed by Dominik that the Doctor's mind was powerful, Ruskovitch promised to kill her and her companions, grabbing a sword and transforming into a huge centaur-like creature in doing so.