Kyra

"Let's see, there was...Kyra. Blacksmith's daughter. She was tall like you, lovely figure, but she talked and talked and talked and...Ramsay grew tired of that."

- Myranda tells Sansa Stark about Kyra

Kyra is an unseen character in Game of Thrones. She is mentioned only once by Myranda in "Unbowed, Unbent, Unbroken.

Biography
Kyra was a daughter of a blacksmith and a servant of House Bolton of the Dreadfort.

Season 5
While giving Sansa Stark a bath before her wedding to Ramsay Bolton, Myranda advises her to not let Ramsay get bored of her or she would "end up like the others." When Sansa asks Myranda what others she is referring to, Myranda first mentions Kyra whom she describes as being tall with a lovely figure but she talked endlessly until Ramsay grew tired of it. Myranda then mentions two seen characters, Violet and Tansy.

In the books
In the books by Kyra was a bedwarmer for Theon Greyjoy after the seizure of Winterfell. When the Boltons put the castle to the sword, they chained the women and children and took them to the Dreadfort. Kyra is manipulated by Ramsay into releasing Reek from his cell, but he successfully tracks them both down as was his intention all along, and kills Kyra. At some point after the hunt, Ramsay names a puppy from the next litter of pack hounds Kyra, as he's wont to do with his "sport".