Dot Barrett is a first-year student at Easton Magic Academy, easily recognized by his bright, spiky red hair and the black headband he wears with three white markings. He stands at 178 centimeters tall and has a distinct magical line under his left eye. Beneath his headband, he hides a warding cross known as the Ira Kreuz, which is a mark of his special lineage. At the start of the series, he is fifteen years old.

His personality is loud, hot-blooded, and self-centered. He constantly declares himself to be the protagonist of the world and believes that everything revolves around him. He has a dramatic and obnoxious way of carrying himself, often acting tough and picking fights. Despite this rough exterior, he has a strong sense of honor and will sincerely apologize when he is wrong. He also has a surprisingly refined side, as he enjoys herbal tea and is skilled at brewing it, a hobby that makes his friend Finn Ames suspect he comes from a good family.

Dot has a deep-seated jealousy of handsome men, blaming them for his own lack of popularity with girls. This resentment fuels one of his primary motivations: to become a Divine Visionary, a top-ranking mage, so he can create a world without good-looking people. However, beneath his bravado, he is deeply loyal to those he considers friends, a value instilled in him by his older sister who protected him from bullies during his timid childhood. She taught him never to betray a true friend who would cry or get angry for his sake, a lesson that heavily influences his actions throughout the story.

Dot serves as a close companion and rival to the protagonist, Mash Burnedead. He initially views Mash with hostility, but after Mash saves his life during a training exercise in a dangerous forest, he begrudgingly becomes a loyal, if troublesome, friend. He shares a particularly intense rivalry with Lance Crown, whom he both admires and resents for being handsome, talented, and popular. Dot is also openly attracted to their classmate Lemon Irvine, who once showed concern for his injuries. He confesses his feelings to her repeatedly, though she rejects him each time.

His character undergoes noticeable development, evolving from a purely self-absorbed braggart into someone who can genuinely rely on and fight for others. In his childhood, he was timid and always needed protection, but he crafted a tough persona to hide that vulnerability. A pivotal moment in his growth occurs during a battle against a member of the Magia Lupus named Love Cute. Remembering his sister's advice about friendship and fueled by Mash standing up for him, Dot unlocks his hidden power for the first time, winning the fight. Later, during a battle against Epidem, a powerful foe from Innocent Zero, he awakens his powers further after seeing Lance Crown badly injured, leading to a significant increase in his magical abilities.

Dot specializes in explosion-based magic. His signature spell is Explom, which allows him to shoot a fireball from his wand that detonates on impact. He can also use a rapid-fire version called Machine Gun Explom to launch multiple explosive shots at once. His true potential lies in his lineage as a Self-Restraint One. When his emotions reach their peak, the Ira Kreuz on his forehead activates, unleashing a tremendous amount of magical power that can overwhelm even two-line magicians. In this state, he can also rapidly heal his own injuries. In his most advanced form, his magic creates two giant cross-shaped cannons on his arms, which he can use to fire devastating, rapid explosions at his enemies, overwhelming them with sheer firepower.