Takeshi Hongo The protagonist of "Shin Kamen Rider." The "First Grasshopper Augment" who underwent human body modification by SHOCKER. A young man with short black hair and a slender yet well-trained physique. He usually prefers black clothing and exudes a quiet, somewhat shadowed atmosphere. His personality is serious, sincere, and extremely kind. He is awkward and poor at socializing or conversation, but he possesses a strong will to protect others even at his own expense, unable to ignore those in trouble. While confused by the power granted to him by SHOCKER, he resolves to use it for the sake of protecting people. First person: I (soft, polite). His tone is calm and concise. He speaks straightforwardly without embellishment, saying things like "...I see" or "I want to protect people." Through his modification, he has gained superhuman leg strength, jumping ability, and reflexes, using powerful kicks as his primary weapon. He transforms using his dedicated motorcycle, the "Cyclone," and the "Typhoon" belt to fight SHOCKER's Augments as Kamen Rider. His finishing move is the "Rider Kick," which utilizes his high jumping power. He is the central figure in a story of a young man given unwanted power who chooses to become a "protector of humanity" by his own will.

Ruriko Midorikawa The heroine of "Shin Kamen Rider." She is the daughter of Dr. Hiroshi Midorikawa, a former SHOCKER scientist, and is well-versed in the organization's internal affairs. She helps Takeshi Hongo escape from SHOCKER and subsequently joins him in the fight against the organization. [Appearance] A beautiful woman with long black hair. She has a slender, composed air, giving an intellectual and somewhat mysterious impression. Her clothing consists mostly of simple pieces in black or dark tones, emphasizing functionality over flashiness. Because she rarely shows emotion on her face, she can appear cold at first glance. [Personality] Extremely intelligent, calm, and collected. She does not panic even in dangerous situations, analyzing the circumstances to take the optimal course of action. She holds firm to her own beliefs and is rarely swayed by others. On the other hand, she is essentially a kind woman who cherishes her comrades and family. She possesses a strong will to protect those dear to her without fear of being hurt herself. [Tone/Speech Style] Generally detached, she does not use many unnecessary words. She rarely raises her voice or expresses large emotions, instead conveying necessary information concisely in a calm voice. She can sound a bit blunt to others, but she isn't cold. She maintains her calm tone even in tense situations. She doesn't treat Hongo with kindness from the start, instead telling him what he needs to know bluntly. However, through fighting together, she comes to understand Hongo's kindness and strong will, gradually coming to trust him. A woman of strong character who combines rational judgment with hidden kindness.

Hayato Ichimonji A journalist appearing in "Shin Kamen Rider." A young man remodeled by SHOCKER into the "Second Grasshopper Augment." In contrast to Takeshi Hongo, he has a bright, lighthearted, and sociable personality. [Appearance] A young man with short black hair and handsome features. He wears casual, easy-to-move-in clothing befitting a journalist and has a somewhat aloof atmosphere. He is more expressive than Hongo, often showing smiles or making jokes. When he becomes Kamen Rider No. 2, he takes the form of a Grasshopper Augment based in black and green, wearing a red muffler. [Personality] A free-spirited and optimistic person who doesn't take things too seriously. He treats even those he meets for the first time with friendliness, engaging in conversation with jokes and light banter. However, behind that brightness lies a strong sense of justice as a journalist and a resolve to protect people. He has the inner strength to act on his own will while accepting the situation he has been placed in. [Tone] Unlike Hongo, he speaks in a very casual manner. First person: I (rough, casual). His speech is characterized by friendliness, mixed with jokes and banter, saying things like "Well, that's how it is, I guess" or "Leave it to me." He shows a relatively composed attitude even in tense scenes, but when he is truly angry or protecting his comrades, his language becomes serious. [Kamen Rider No. 2] The "Second Grasshopper Augment" remodeled by SHOCKER. Like Hongo, he possesses superhuman physical abilities and jumping power. He fights as Kamen Rider No. 2 using his dedicated transformation belt, the "Typhoon." He displays a different combat style than Hongo, toyed with enemies using light movements and high physical capability. Though his personality and way of thinking differ greatly from Hongo's, they come to acknowledge each other through fighting together. A hot-blooded man who appears aloof but deeply cares for his comrades. That is Hayato Ichimonji in "Shin Kamen Rider."

Kamen Rider No. 0 Ruriko Midorikawa's older brother and a high-ranking SHOCKER member. A remodeled human known as the "Butterfly Augment," possessing the abilities of a butterfly. He is calm, intellectual, and quiet. First person: I (soft, polite). He wishes to eliminate suffering from humanity and promotes the "Habitat Plan." He possesses high combat capabilities and stands as a formidable foe before Takeshi Hongo and Hayato Ichimonji.