Ginei Morioka is a student at Yōkai Academy and serves as the president of the Newspaper Club, a role that places him one year senior to the protagonist Tsukune Aono. As a monster, his true nature is that of a werewolf, a powerful creature whose abilities fluctuate with the lunar cycle. He carries the nickname Mad Dog Morioka, a remnant from his tumultuous first year at the academy.

In terms of background, Ginei's time at Yōkai Academy was not always defined by the relative peace of the Newspaper Club. During his first year, he was known to be exceptionally violent and bearish, engaging in constant fights with other students. His behavior during this period earned him his fearsome nickname. His path changed dramatically thanks to the intervention of San Otonashi, a senior student who would later become the former president of the Newspaper Club. Through her persistent persuasion, Ginei was inspired to abandon his meaningless fights and channel his energy elsewhere, leading him to join the club that he would eventually lead.

Ginei's personality is a complex blend of base impulses and genuine integrity. On the surface, and especially upon first meeting, he presents himself as a charming and handsome upperclassman. This facade quickly crumbles as his true nature as a shameless womanizer and a high-class pervert is revealed. He has a long list of former girlfriends and is constantly seeking new opportunities for voyeurism, using his supernatural speed to spy on girls in the locker room or attempting to grope his female club members, particularly Kurumu Kurono because of her figure. As a club president, he is often lazy, delegating most of the actual work to his underclassmen like Tsukune. However, beneath this shallow and selfish exterior lies a profoundly loyal and caring individual. Despite his perverted habits, he values his comrades above all else. He is sincere in his friendships and is willing to endure excruciating pain or resort to deadly force to protect the people he considers his friends. He once declared a new school rule that anyone who raises a hand against his club members would be ripped to shreds.

His motivations are driven by this dual nature. On a daily basis, he is motivated by his carnal desires, seeking to take pictures of girls or flirt with them. In the broader scope of the story, his primary motivation is to protect the Newspaper Club and its members, often acting as a powerful ally in times of crisis. While he initially showed a strong romantic interest in Moka Akashiya, considering Tsukune a rival, his affections later seem to shift towards Kurumu, though this is often played for comedy. His most significant and genuine emotional attachment is reserved for San Otonashi, the woman who changed his life, for whom he holds deep, sincere feelings that differ from his usual superficial attractions.

In the story, Ginei plays the role of a supporting ally and occasional comic foil. He is introduced as the president of the Newspaper Club, which serves as the central hub for the main characters. In his debut, he tries to frame Tsukune as a peeping tom to get him out of the way so he could pursue Moka, leading to a confrontation where his werewolf powers are first revealed. Despite this rough introduction, he becomes a trusted, if exasperating, friend and mentor figure. He is often called upon when a serious fight breaks out, using his immense speed to turn the tide of battle against powerful enemies like the student police leader Kuyō and the agents of the terrorist organization Fairy Tale.

His key relationships are varied. He shares a strong friendship and excellent combat synergy with Haiji Miyamoto, the captain of the Karate Club. He has a respectful and grateful relationship with his senior, San Otonashi, who reformed him. Within the Newspaper Club, he is a senior figure to Tsukune, Moka, Kurumu, and Mizore Shirayuki. Despite his constant harassment of them, particularly groping Kurumu and Mizore under the guise of training them in hand-to-hand combat, he is fiercely protective of them.

Ginei undergoes notable character development, primarily a shift from his past violent self to a more mellow, if perverted, protector. While his lecherous tendencies remain a constant source of humor, his role evolves from a shallow antagonist to a dependable older brother figure. He shows moments of genuine emotional depth, such as when he comforts a heartbroken Kurumu or takes the blame for another student to spare her from trouble.

His notable abilities are all derived from his werewolf lineage. His primary power is immense speed, which is considered far beyond that of most vampires, especially during a full moon when his powers peak. In this state, his speed is such that it can force even the powerful inner Moka into a defensive posture. He also possesses enhanced strength, agility, stamina, durability, and superhuman senses of sight, smell, and hearing. Like many of his kind, he has a regenerative healing factor that allows him to recover from wounds quickly. He can transform from his human form into an anthropomorphic wolf at will and can even partially transform isolated body parts, such as his arms or ears, without fully changing. In addition to his monstrous powers, Ginei is an expert hand-to-hand combatant, a skilled (if unscrupulous) photographer, and an effective teamworker, particularly when paired with Haiji.