Age: 15-16
Height: 168 cm
Classification: neither Esper nor Magician; a normal human with a unique ability
Ability: Imagine Breaker
Level: 0
Famous Quote: It's my dream to go back home smiling, without having lost anything.

He is the series' protagonist. He has the lowest psychic rank possible at Level 0—largely because the people testing psychic abilities cannot detect or classify his abilities. His power is Imagine Breaker (幻想殺し, "Illusion/Fantasy Killer"), a power which negates all magic, psychic, or divine powers but also his own good luck. Due to the nature of his power, the founder of Academy City considers him neither a Psychic nor a Magician but rather a normal person with a unique ability.

He tends to stay away from trouble but possesses a strong sense of justice, albeit somewhat shallow and dogmatic. He is a smart student and knowledgeable about certain subjects yet is a failure in his esper studies. While he is an idealist for the hopes of other people, ironically he is cynical about himself possibly because of his powers.

In order to save Index from the need of a memory reset, he had activated her self-protection system and destroyed the spell responsible for her mind strain but ends up having his memories destroyed when he came in contact with Feather of Light (光の羽, Hikari no Hane?). Though he no longer remembers the past, he claims his heart has not completely forgotten the people he cares about. His memories lost is kept a secret except himself and only a few know, which include his doctor (who unknown to Tōma, is Heaven Canceler, Aleister's personal physician), his parents after telling them the truth during the Academy City Sports Festival, Terra of the Left who manage to figure it out by himself and recently, Mikoto when she learns about it from an accidental phone conversation between him and Terra and confronted him about it and forced him to tell the truth.
Throughout the series, he tries to live his life normally while still facing against the many adversaries from the worlds of science and magic and the conflicts that follow. Despite his very bad luck, he has managed to get the interests and hearts of many ladies who are infatuated with him, which Aisa jokes about, that his life is like a dating sim where he is bound to unlock more paths to more girls.
One of the series' main mysteries is the origin of Imagine Breaker, since it is neither an esper ability or a magical ability. Later in the series, it is hinted to be of Divine origin according to two members of God's Right Seat. Fiamma believes Imagine Breaker is the container for his Holy Right, which holds the power of miracles and Terra hints Imagine Breaker's full powers have yet to be unlock; if it does, its powers would extend to Touma's whole body and beyond.
In NT volume 11, Shokuhou Misaki found herself being chased by a group called Deadlock who wanted to kill her. Touma stood to protect her even after they offered to let her go, but was heavily injured in the process. On the verge of dying, Misaki used her Mental Out to cut off his sense of pain so that the EMTs could save him, as he received a radical drop of blood pressure. Touma's life was saved, but as a price, his "pathways that call in the memories" were damaged causing him to lose his memories about Misaki and making him unable to remember her even after other future encounters.
(Source: Wikipedia)