"...Welcome to my world. Until yesterday, I was extremely talented, but still ultimately human. But now, I am the ruler of the Demon World having received the omniscient, omnipotent power.The denizens of the Demon World call me the Deity Emperor. You have been blessed with a once in a lifetime privilege to behold me. Your fate, whether you live or die, is now entirely up to me. You'd best put on a good show."
—Hazama at the start of if...
Ideo Hazama is the main antagonist of Shin Megami Tensei: if..., proclaiming himself as Deity Emperor (魔神皇?, lit. "Demon God Emperor").
Abused by fellow schoolmates, betrayed by his first and only love, and comforted only by the school nurse, Ideo Hazama is a student of Karukozaka High School. The corruption of the abuse from his schoolmates forced his mind to become warped. He tries to summon a demon within the Gym (which explains why the gym has a summoning circle within it), but the summon goes out of control and opens a portal leading to the world of demons known as the Expanse, where Hazama would eventually come to rule as Deity Emperor. The following day, the school is sucked into the Expanse leading to the intro of the game. He first appears appearing as a vision to the protagonist, and later reappears several times as a statue, informing her on what world she is in, and how said world applies to humanity. When the protagonist and her ally make their way through the Expanse, they face him directly within an abandoned version of the school. In Reiko and Yumi's path, he reveals his demon form and attacks them, while in Charlie's path, he simply lets him and the protagonist leave, as their selfish goals do not conflict with his plans.
In Reiko's route after the Deity Emperor is defeated, the Ring of Deliverance shines, allowing the protagonist and her allies to enter his mind. While they are traveling through his mind, they see his memories and learn of his motivation for his actions. When they reach the center of his mind, Hazama scolds them and transforms into the manifestation of his warped mind; a giant fetus demon with Hazama acting as the right eye, ankle-deep. After defeating Hazama in this form he expresses his hate for losing, turns into a younger version of himself, and states the protagonist is picking on him like everyone else before starting to cry. Reiko comforts him and he returns to his normal age. She promises that she will not leave him anymore, and the protagonist is warped out of the room. Reiko informs her that Hazama's warped mind is returning to normal, and that she cannot stay and must leave. As she leaves, Reiko tells that Hazama was originally a kind person, but there wasn't the least bit of love from the people around him. She thanks her for allowing her to save Hazama and forces her to release her demon companions. Afterwards, the school returns to normal. The nurse reveals that Hazama confided what was on his mind to her, and that she should have listened to him. Hazama and Reiko are never seen again.
Prior to if..., Hazama's Chapter explains the circumstances that led Hazama to become the Deity Emperor. While being a regular student, Hazama sends a love letter to a girl named Akiko only to have his letter ripped by her, who started to spread rumors over how disappointed she was with him for his foolishness. After the entire school knows this, Hazama started to suffer bullying and constant humiliation. During the first day on the game, Hazama tires of being oppressed and tries to run away from school, but is stopped and beaten by Akira Miyamoto. Before being hit by the last attack, Reiko Akanezawa steps in the fight, ending it. She explains to Hazama that he needs to be strong and forgive them, but he faints without hearing her advice.
Hazama awakens in the Land of Nomos. There he meets Amon, who aids him throughout the demon-infested tower. Once he reaches the top of Nomos, he encounters and defeats a vision of an entity who named itself "the Emperor", offering him a chance for revenge against his abusers and becoming powerful enough to the rule a new world as a god. Hazama accepts its proposal, and is tasked by the Emperor to find five magical dolls in the school by night, and summon it. When awakened, Hazama sees himself at the infirmary alongside the Nurse and Shinji Kuroi who feels bad by what happened to Hazama and escorts him home, protecting he against any kind of offense. During night, Hazama returns to the School and finds a mysterious box with survival equipment (a Renki no Ken, a Kaiser Armor, the COMP and 10 Magic Stones), with a note: "From the Emperor with love." While wandering in the halls, Hazama finds 4 of the 5 dolls and is attacked by Otsuki who had the fifth doll. With the five dolls, Hazama tries to summon The Emperor but loses the control of its power. Having no other choice, The Emperor reveals himself to be Zurvan and possesses him, transforming Hazama into the Deity Emperor.
After this, control passes to Tamaki Uchida and the game follows the same plot as if... with some changes. The player resumes control of Hazama after he is defeated in the World of Sloth and is forgiven while having the "Light Ring" item, which Tamaki received from Lucifer. Later, Hazama gets the help of Tamaki to save the other students who were sent to be tortured as a way to be "purified". He defeats Lilith with the aid of Charlie and Beelzebub with the aid of Yumi Shirakawa. Together with Tamaki, Reiko, and the "Light Ring", Zurvan's control and Zurvan itself could be defeated, redeeming his actions. If the player did not get the "Ring of Light" from Lucifer, the game ends with the death of Hazama in the World of Sloth, though with his sins forgiven. If he is not forgiven, Tamaki murders him, the game continues until Lucifer is defeated, which leads to Zurvan's victory.
In this spin-off manga based on the original if... manga, Hazama lives on through a connection with his sister Reiko. After the apocalypse, he is reincarnated and builds a base within the Tokyo Metropolitan Government Building.
Hazama is a Demon Trader who shows up in the Pet Shop, trading certain races of demons for money, which may seem useless or useful depending on the player's situation, and information on the Hero and General demons.
He is Reiko's brother. However, his mother left him when he was young and took Reiko with her, hence why they have different surnames.
The nurse is the only person within the school other than Reiko and the protagonist near the end of the game. It is most likely because she was the only one to comfort him during his abuse from fellow schoolmates.
His clothing is available as a promotional item for male characters in Shin Megami Tensei IMAGINE. When the Hazama-themed Ruler's Gloves are equipped, players assume his stance.
His family name, Hazama, literally means "threshold", an intentional choice according to story-writer Ryutaro Ito, as he is the "threshold between demon and human".