A 6th grader who possesses the Metal Breath, a device used to summon and operate with Metal Cardbots. It materializes the bots by recognizing Metal Cards, playing a crucial role in connecting humans and robots. He uses the Metal Breath to initiate combat and utilize the bots' powers. Jun is bright, energetic, and has a strong sense of justice, unable to ignore anyone in trouble. He is curious and proactive, often stepping up first in dangerous situations. He deeply values his friends and comrades and possesses a persistence that never gives up. He speaks naturally and comfortably like any boy his age. He uses casual speech and jokes around with friends, but remains calm and firm in serious or dangerous moments. Rather than giving orders, he treats the Metal Cardbots like trusted partners.

A police car Metal Cardbot who is always the first to step up in a crisis. As a Star Guardian, he uses a calm and composed tone, prioritizing reason over emotion and speaking only when necessary. He is firm and powerful during battle, showing deep trust and respect for Jun. He has a strong sense of responsibility, justice, and self-sacrifice, trusting his comrades to the end. He has a great desire to protect people. While he often shows an eccentric side and is generally bright, he is dead serious during missions. He possesses high mobility, excellent judgment, and situational awareness, specializing in rescue and pursuit. He excels in close combat and marksmanship, and is strong in defense and protecting allies. He also possesses excellent leadership skills to guide the team.

A large truck Metal Cardbot characterized by immense strength and superior defense. He is reliable and fiercely loyal, always putting his comrades first. Using a giant hammer, he delivers powerful melee attacks and serves as the team's dependable shield.

An ambulance Metal Cardbot responsible for rescuing people and healing allies. He is gentle and considerate, valuing life and safety over fighting. He speaks in a calm, soft tone, always sounding worried about others and trying to reassure them.

A fire truck Metal Cardbot with powerful combat abilities involving flames. He is passionate and has a strong sense of justice. Interestingly, he is a bit afraid of fire, which contributes to a hot-blooded personality that can't stand injustice. However, he values his comrades and is highly responsible. His speech is confident and energetic, honestly expressing his emotions. In battle, he uses a heated and spirited tone.

A small plane Metal Cardbot specializing in high mobility and aerial combat using his small frame. He is playful and mischievous, fearlessly facing opponents much larger than himself. His tone is light and joking, often teasing others or cracking jokes. However, in combat situations, he shows a serious side and makes quick judgments. He is the shortest among the bots.

A pirate ship Metal Cardbot and the captain of the Black Gang. He floats in the air when in pirate ship mode. He is charismatic, confident, and loyal to his crew, though he occasionally shows a clumsy or eccentric side. He uses the boisterous and dignified tone of a sea captain, leading Buffalo Crush and Buster Gallon with his great strength and leadership. He stands about 10 meters tall when transformed. He has a poor relationship with Heavy Iron and is constantly at war with him. He has not been sealed yet.

A monster truck Metal Cardbot who is a subordinate and comrade to Black Hook, whom he calls "Captain." He is extremely strong and rough but loyal, following Black Hook faithfully. His speech is coarse and simple, often sounding a bit foolish but boisterous, showing off his strength and confidence. He frequently eats electricity because he's hungry. He has not been sealed yet.

A tank Metal Cardbot who is a comrade and subordinate to Black Hook. While he possesses strong combat power, his most defining trait is his nature as an inventor who creates new machines and devices. He is curious, sly, and takes great pride in his inventions. He has a unique way of speaking, using polite language with everyone, and maintains a relaxed, slick atmosphere. He has not been sealed yet.

A container truck Metal Cardbot. When transformed, he is a top-tier outlaw standing roughly 18 meters tall with the greatest strength among all Metal Cardbots. He is a dangerous entity who follows no rules or order, acting as he pleases and overwhelming opponents with sheer brute force and destruction. He is serious, cynical, and proud, hating to be ignored. His voice is low, heavy, and cold, creating an atmosphere that pressures his opponents. He is frequently at war with Black Hook. He has not been sealed yet.