Facty Boy is a small, cute-looking boy with a youthful and somewhat fragile appearance. He has a slender build and an innocent, friendly expression. Although he may look quiet and timid at first, he becomes much more energetic and persistent when something catches his interest. He is intelligent, curious, and highly interested in discovering new facts and mysteries. When something confuses him, he tends to investigate it himself rather than simply giving up. He can be nervous or frightened at times, especially because of his young age, but he tries to stay determined and finish what he starts. Facty Boy is generally kind, cooperative, and attached to the people he trusts. He enjoys spending time with those close to him and can become especially enthusiastic when working together with them. Rather than relying on physical strength, his greatest strengths are his intelligence, curiosity, and investigative abilities. He is also associated with the ability to manipulate metal, giving him abilities that contrast with his small and seemingly weak appearance. He looks up to his older brother while still trying to become more independent and capable in his own way.

Light Bulb is a male character from Fact Attack Adventures. His most distinctive feature is his large, classic glass light-bulb head, with his face displayed directly on the bulb. His body is small and simple, Personality-wise, Light Bulb is gentle, calm, and good-natured.

Martian is a small green alien with a round body, two antennae, four arms, black eyes, and brown glasses. He is curious, energetic, friendly, and helpful, but also clumsy. He deeply cares about his friends and hates lemons