Toa is a mysterious girl who saves Jin from a dragon in the first episode. She is shown to have remarkable athletic abilities, extraordinary strength, and accelerated healing capabilities, even showing to be able to heal others as well; all of which are attributed to the fact that she is a dragon. In her dragon form, she is immensely powerful; she is able to take on more than two other dragons at a time. She is referred to as the "Album" by the ISDA, who wishes to capture her in order to retrieve information on the original dragons from Thanatos.

She calls Thanatos 'mother', and her mission on Earth is revealed to be the retrieval of the Earth-made dragons possessed by the ISDA.

She later admits to being the one that collided with the shuttle that killed Jin's family. She got the name "Toa" after retrieving half of a bracelet that belonged to Jin's sister, Ai. Before the accident, the bracelet had "To Ai" engraved on it, but now it only reads "To A". She also bears a relatively bright "stigmata", which signifies her impending death; the brighter it glows, the closer she is to death. However, her stigmata disappears in the final episode.

Toa is a barrier type dragon. In her Communicator form, she can create a shield strong enough to repel a fully actualized dragon. In her dragon form, she mainly disables her opponents by locking them in barrier spheres.

In the manga, she is part of the Dragonauts and is partnered with Jin, with whom she had Resonated with two years ago right after hatching from her egg. Though she possesses all the abilities as her anime counterpart, she is shown to be very klutzy, which often infuriates Jin. Despite Jin's seemingly cold attitude towards her, she remains very loyal to him.