Eiichi Suou is introduced as a former champion coach who has since fallen into a state of burnout, characterized by heavy drinking and a disheveled appearance often completed by his traditional geta sandals. He enters the story when Masayo, a figure connected to the world of Neo Pro-Wrestling, recommends him to train the aspiring team known as the Pretty Four. Despite his lackluster exterior, Suou possesses a deep understanding of the sport and a sharp eye for talent.

Suou's personality is gruff, blunt, and unyielding. He does not coddle his trainees and has little patience for ego or complaints, often responding to the team's resistance with a straightforward, no-nonsense attitude that places him in stark contrast to the more flamboyant elements of the wrestling world. A central trait is his alcoholism, which reinforces his image as a broken-down veteran, yet this flaw does not diminish his credibility as a coach. His primary method of training relies on intense, almost inhuman physical discipline, such as ordering hundreds of push-ups and sit-ups, which is initially met with resistance from the team. While his methods appear simplistic, they are grounded in a philosophy of building foundational strength and resilience, and he occasionally devises more unique regimens, such as oceanic training with scuba gear.

The core of Suou’s motivation lies in the potential he sees in the protagonist, Miku. He is depicted as having previously coached Aquamarine, a legendary champion, and he detects a similar inner fire within Miku that rekindles his own purpose. His role in the narrative is that of a catalyst for the team's growth, pushing the Pretty Four to move past mere popularity and develop the genuine strength needed to compete at the highest level. He is portrayed as one of the characters with the greatest depth, possessing an interesting backstory that explains his current state and his obsessive drive to prepare Miku for a final confrontation with his former student, Aquamarine. This connection to Aquamarine represents a significant relationship in his past, and his desire to see Miku defeat her forms a central pillar of his character arc.

Throughout the series, Suou’s development is subtle but noticeable. While he begins as a seemingly apathetic drunk, his consistent presence and investment in the team’s success reveal a more complex figure who genuinely cares about their progress, even if he rarely shows it in a warm manner. He serves as the strategic and philosophical anchor for the team, often providing the necessary insight to overcome psychological barriers in addition to physical ones. His notable abilities lie not in physical combat, but in his analytical mind, his capacity to devise effective training and tactics, and his ability to recognize and cultivate raw talent in his wrestlers.