Keima is a high school student at Maijima Private High School, where he is socially isolated due to his obsession with gaming. He spends almost all his time playing dating sims, developing an encyclopedic knowledge of various routes, character archetypes, and romance mechanics. His reputation as the ultimate gamer comes from his ability to “conquer” any girl in any game, never failing to reach the optimal ending.

One day, Keima unknowingly accepts a challenge to conquer real girls, believing it to be a gaming-related request. However, this activates a contract with the demon Elsie, binding him to capture lost spirits that reside in the hearts of real girls. The only way to drive out these spirits is to make the girls fall in love with him a task he initially detests but gradually becomes more invested in.

Despite his cold and calculated nature, Keima is forced to navigate the complexities of real human emotions, pushing him into unexpected character growth.

Keima has a slim build, short brown hair, and sharp brown eyes that often carry an uninterested or calculating expression. His defining feature is his red-rimmed glasses, which he rarely takes off. His usual attire consists of his Maijima High School uniform, which includes a brown blazer, white dress shirt, and red ascot tie, giving him a distinct and somewhat old-fashioned look.

When deeply immersed in his gaming world, Keima is often seen wearing headphones and multiple handheld gaming consoles at once, showcasing his unwavering devotion to his craft.

Keima is analytical, intelligent, and extremely dedicated to gaming, often displaying overwhelming confidence in his abilities. He considers 2D girls superior to real-life women, as they follow predictable patterns and logical routes, whereas reality is messy and irrational. His cold and detached demeanor makes it difficult for him to form genuine relationships, and he often prioritizes gaming over everything else even during life-threatening situations.

However, despite his self-proclaimed disdain for reality, Keima is not entirely emotionless. As he interacts with real people, he gradually begins to understand the complexity of human emotions, developing a deeper sense of empathy and responsibility. Though he remains logical and goal-oriented, he learns to appreciate the unpredictability of real-life experiences, even if he refuses to admit it openly.

His most defining trait is his strategic mindset he approaches every romantic conquest as a game to be solved, meticulously analyzing personality types, behaviors, and optimal responses to ensure a successful outcome. This level-headed, calculated approach makes him shockingly effective at real-life romance, even if he doesn’t personally enjoy it.

• The Forced “Conquest” Missions
  Keima’s life changes when he is tricked into signing a contract with Hell, requiring him to capture runaway spirits that hide in the hearts of emotionally vulnerable girls. With Elsie, a cheerful and clumsy demon, as his partner, he must win the hearts of real girls, forcing him to apply his dating sim expertise to real world scenarios. Initially, he views these missions as a hassle and refuses to engage with them emotionally. However, as the series progresses, he begins to develop a deeper understanding of human emotions a realization that challenges his rigid, game-like perspective of the world.

• The Goddesses Arc: Raising the Stakes
  As the story unfolds, Keima’s conquests become more serious, especially when he discovers the Goddess Hosts, a group of girls who unknowingly harbor divine beings. Their memories of Keima’s past conquests are intact, making his usual strategy ineffective. This arc pushes him to his mental and emotional limits, as he must juggle multiple real relationships at once, all while facing high-stakes supernatural threats. During this arc, Keima’s character development is most profound he begins to question his detachment from reality and faces genuine heartbreak for the first time. Though he ultimately succeeds in saving the Goddesses, the emotional toll leaves a lasting impact on him, proving that he is not as unaffected as he pretends to be.

• The Final Conquest: Confronting His Own Reality
  By the end of the series, Keima fully realizes the weight of his actions. Though he once treated love as a mechanical game, he now understands that real emotions cannot be reset like in a dating sim. Despite his growth, he chooses to return to his gaming world, believing that reality is still too unpredictable for him to handle. However, his experiences have undeniably changed him, making his final decision bittersweet while he remains a devoted gamer, he is no longer completely disconnected from the real world.