OVA
Description
Before being transported to the world of El-Hazard, Katsuhiko Jinnai is a third-year high school student serving as the president of the student council at Shinonome High School. Standing approximately 174 centimeters tall and born in April 1978, he is an intelligent and ambitious individual whose primary grievance on Earth is his classmate and rival, Makoto Mizuhara. Jinnai views Makoto as his sworn enemy because Makoto consistently outperforms him in academics and athletics, a fact that fuels a deep-seated grudge and an inferiority complex. While serving as student council president, Jinnai engaged in corrupt practices, such as illegally promising school funds to clubs in exchange for votes, and it is during the subsequent attempt to silence Makoto and prevent his own impeachment that the pair are transported to another dimension.

Upon arriving in the fantastic world of El-Hazard, Jinnai acquires a unique ability that defines his role in the new realm: he can communicate with the Bugrom, a race of giant, humanoid insectoid beings. No other human in El-Hazard shares this capability. Believing him to be a divine messenger sent to lead them to victory, the Bugrom Queen, Deeva, willingly cedes military command to Jinnai, who quickly ascends to the position of general and commander-in-chief of their army. Possessing a keen strategic and tactical mind, Jinnai reorganizes the previously disorganized Bugrom forces into an effective and formidable army, successfully conquering much of El-Hazard and posing a significant threat to the human kingdom of Roshtaria.

Jinnai's personality is defined by egocentrism, dishonesty, narcissism, and an almost psychotic obsession with power and his rival, Makoto Mizuhara. He is power-hungry, ruthless, and manipulative, yet he tempers these traits with a sharp wit and considerable intellect. His primary driving motivation is the conquest of El-Hazard, which he sees as his rightful dominion, and the subsequent defeat, or even destruction, of Makoto, whom he blames for every failure and misfortune in his life. Despite his immense confidence and grandiose self-image, he is prone to dramatic outbursts and possesses a very distinctive, memorable laugh.

His key relationships are defined by rivalry and alliance. His hatred for Makoto Mizuhara is the central axis of his character, and he views every setback through the lens of Makoto having bested him again. Conversely, his relationship with the Bugrom, particularly Queen Deeva, is one of mutual convenience. While he commands their forces, he displays a notable degree of respect for his insectoid soldiers, often treating them less like disposable minions and more like valued subordinates. He takes the time to give individual names to many Bugrom soldiers and is even known to accompany them into battle, a rare show of camaraderie that suggests a hidden paternal instinct toward his troops. His dynamic with his younger sister, Nanami, is contentious; she is far more morally grounded and often acts as an antagonist to his schemes, even exposing his corruption on Earth.

Throughout his journey, Jinnai's character shows subtle layers beyond pure villainy. For example, he once rescues Makoto and his allies, not out of altruism, but because he believes a true ruler does not destroy the land he wishes to conquer. In a desperate moment, he even seeks to gain control over the ancient and powerful demon god Ifurita, briefly becoming her master before being thwarted by Makoto. These actions reinforce his role as the primary human antagonist in El-Hazard, a cunning and relentless strategist whose quest for power and revenge makes him a formidable force within the magnificent world.