Theo (JP: Teo)
Age: 10
Hometown: Renn, Forestamore
Family: mother (deceased), father (assumedly deceased)
Hair: Dirty Blonde
Eyes: Brown
Weapon(s): Spears, Cards
Distinguishing Features: Big spear, Cardist powers

Theo grew up around Renn with his mother, who was an amazing Cardist- that is, she had the ability to capture monsters inside cards and then release their powers when she wanted to or needed to. Theo's mother disappeared one day, and was never heard from. Ever since that day, Theo's dream has been to become a Cardist like his mother, but the watchful head of the Renn Monster Society feels responsible for Theo and doesn't want the boy getting into any unnecessary danger. When Alec and Lutz come to Renn on business, Theo sees how much the duo has accomplished while still so young, and his Cardist dreams are renewed. He runs off to the Great Scar, a giant crater left as a remnant of the Great Disaster and, though he puts himself in danger, he accomplishes his dream and receives Cardist powers. Though young and sometimes immature, Theo is fiercely loyal to the team and wants to prove that he can help out in any way possible.