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 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. Although angered over a plan she had supposedly not working, she was calmed by a monk called Dominik. Once everyone had arrived at the party, she greeted them, but concerned about the meeting, the Doctor introduced herself and asked why everyone could suddenly speak each other's languages. The question was quickly shrugged off and she later met Kepler and Yaz, inviting Kepler to a private showing of her literary collection.

In her 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 Tycho, Graham and Yaz, where she realised their connection to the Doctor and promised to kill her and her companions, grabbing a sword and transforming into a centaur in doing so. However, she was stopped by Kepler and agreed to spare their lives while taking him with her, throwing everyone else in the dungeon. She later distributed her orbs to the rest of the gatherers, which began paralysing them. With her plan in action, she controlled Kepler as a huge hand appeared out of the castle's lower chamber. However, Graham and Yaz shattered the orbs, with Ruskovitch immediately blaming the Doctor. Finally meeting the Doctor, she transformed into a centaur again to kill her but was trapped by a falling bookcase. In doing so, she told the Doctor she had doomed the planet, as she did not summon the creature, but was actually attempting to prevent it from appearing. (COMIC: Herald of Madness)