Plym Machina is a female character in the anime and manga series Battle Spirits Brave, and she also appears in the later installment Battle Spirits Saga Brave. During Battle Spirits Brave she is a thirteen-year-old girl, while in Saga Brave she is shown at twenty-three. She has red-orange hair that reaches about ear length and red-orange eyes. Her outfit consists of a black top that covers her hand with only finger holes and is cut around the shoulders, along with brown pants that appear to be tied over the top with green straps.

Plym had never played Battle Spirits before the events of the story, which sets her apart from the card-battling main characters. Her enthusiasm is directed instead at the spirits themselves, particularly mechanical spirits, which she considers especially cool. She is also inclined toward hands-on construction, and while on board the Sophia she builds a model of the spirit Grand-Woden, showing both her skill and her attachment to machine-type designs. This love of mechanical things is so closely tied to her identity that even her musical theme carries a playful phrase that blends the words for mecha and cool.

Because she does not play the card game, her role in the narrative is not tied to battles. Her presence is defined by her passion for machines and her ability to create mechanical works, rather than by dueling skill. Her later appearance in Battle Spirits Saga Brave, as an adult in her twenties, reflects the passage of time and shows that she remained part of the story's world after the events of Battle Spirits Brave.