Ikuma Amaki, often nicknamed Makki by those close to him, is one of the five main members of the idol group Shōnen Hollywood and serves as its leader. He is physically characterized by his brown hair, which is cut to ear-length, and green eyes. Ikuma has a distinct and somewhat contradictory background, having been a Yankee, or Japanese delinquent, before entering the entertainment industry. His past is directly tied to his departure from formal education, as he dropped out of high school following a physical altercation with other members of his former delinquent group. This lack of completed schooling manifests in his daily life as an adult, as he can be notably clumsy with academic subjects and sometimes struggles to correctly read or differentiate kanji characters.

Despite this rough history, which might suggest a stern or threatening personality, Ikuma is far from ill-natured. He is generally portrayed as a somewhat lazy and airheaded individual who enjoys lazing about and is a source of humor for his group mates with his absentminded antics. He maintains a cheerful disposition, though this belies a short temper that can flare up when he is provoked, revealing a stubborn and hot-headed side. Fundamentally, he is a person who cares deeply for his friends, often showing more concern for their well-being than for his own. His personal motto is Rome wasnt built in a day, reflecting a patient, if perhaps relaxed, approach to his ambitions.

Within the story, Ikuma holds the prominent center position during the groups performances, a role that demands strong presence. However, his transition from a delinquent life to that of a professional idol is not without its challenges. He has significant difficulty learning the choreography for the groups dance routines, an area he struggles with more than his bandmates. His primary motivation is the success of Shōnen Hollywood; his dream is for the group to become the most popular in the world. He is also known for having an eccentric and overwhelming obsession with Cat, the pet owl that lives at the Hollywood Tokyo Theater where the group performs and rehearses. A long-standing personal goal of his is to one day carry the reluctant owl on his shoulders. In terms of practical abilities, beyond the singing and performance skills required of an idol, Ikuma does not possess any supernatural powers or special combat training, though he retains the capability for a typical street fight from his Yankee days.