Okabe Rintaro

In the gamma attraction field, Okabe is a Rounder, and we know that by the year 2036, he becomes the leader of SERN's security forces, a member of the Committee of 300, and the dictator Hououin Kyouma, who rules Japan with an iron fist.
In the visual novel Steins;Gate 0, it is revealed that Okabe is an engineering student.
He loves drinking Dr. Pepper, but in the gamma attraction field, his favorite drink is Mountain Dew.
The reason he doesn't call Kurisu by her real name, but by various nicknames, is because he was too embarrassed to call her by her real name.
The actions of the Committee of 300 in the Science Adventure universe fit Okabe's delusions almost to the letter.
The visual novel explains that his surname "Hououin" comes from the Japanese equivalent of the mythical firebird, the "Phoenix," which is pronounced "Hou-ou." "Kyouma," on the other hand, comes from "horrible truth" or something like that.
He claims to have an IQ of 170. For reference, 145 is considered the genius level of intelligence.
In the future of the Alpha worldline, Okabe became the leader of the resistance against the SERN government and was known as an international terrorist (in the parallel story The Far Valhalla, it is revealed that SERN released Okabe and Daru so they could found the resistance, thus completing the cycle of destiny). Okabe was captured by SERN's Rounder unit in 2025 and tortured to death.
In the Steins;Gate 0 drama CD, Runaway of the Free Particles 01 (The Conference), Okabe demonstrates that he knows how to improvise when it comes to rapping.

Meanwhile, Kurisu and Daru are working on the Time-Travel Machine, an improved version of the Microwave Phone that can send the user's memories to the past. Additionally, Okabe has been receiving threatening emails from an unknown sender, each containing disturbing images. Finally, on August 13th, the Futuristic Artifact Lab succeeds in creating the revolutionary device, which they decide to unveil publicly and donate to a suitable research institution. Beforehand, they celebrate their achievement with a party that evening, which is also attended by Suzuha Amane.

Their celebration, however, was cut short by news of a bomb threat on the subway lines leading out of Akihabara, an incident Okabe noted was unusual for Japan. Suzuha became alarmed and left the apartment after hearing that their time machine was finished. Shortly after, a group of mercenaries led by Moeka entered the lab to deliver the time-travel machine and its inventors, Okabe, Daru, and Kurisu, to SERN, while Mayuri was killed to silence her. Overwhelmed by this unexpected turn of events, Okabe seized the first opportunity to send his memories back in time after Suzuha helped him by turning on the 42-inch CRT television in the shop and taking down the enemies and stopping Moeka. But no matter how many times Okabe traveled back in time, the result was always the same: Mayuri inevitably died.

After encountering Moeka, a shy woman who communicates only through her cell phone, on the street, Okabe learns about the IBN 5100, an ancient and extremely rare computer that might be in Akihabara. Okabe also orders Daru to hack into SERN to find information related to the supposed time machine that Titor mentions online.
To their surprise, SERN has been researching time travel for years and has even conducted several experiments on humans, all of whom they have managed to send to the past, but none have survived and upon arriving at their destinations, their bodies have turned into jelly and they have appeared in different places; Daru also finds a suspicious database on SERN's servers, but he is unable to decipher its code, so Okabe decides to ask Titor about it, confirming that SERN is taking advantage of the hidden function of the IBN 5100 to hide its secrets.
Okabe proceeds to search for the computer in Akihabara, eventually finding it at Yanabayashi Shrine. He takes it to the lab with Kurisu for Daru to analyze. However, as more lab members join and send more D-Mails, Okabe realizes he has lost the IBN 5100, and its whereabouts are now unknown. Due to the "butterfly effect" triggered by the messages sent to the past, Okabe finds himself in a timeline where the computer never reached the shrine, and therefore, he never found it. Adding to this, there's also Luka's gender reassignment and the complete shift of Akihabara's economy to exclusively electronics, the latter being a consequence of Faris's D-Mail.

From this point on, Okabe begins to encounter more unexplained phenomena, such as his memories not matching those of others, the sudden appearance of the satellite embedded in the eighth floor of the radio building, which caused the cancellation of Dr. Nakabachi's lecture before it even began, the email he sent to Daru that same day being sent back a week in time, and Kurisu Makise being found alive and without any signs of physical harm; the latter results in Kurisu joining Okabe's lab after he pretends to be stalking her in his astonishment at seeing her standing up; Okabe makes her lab member 004 to help them discover the theory behind the strange function of the Microwave Phone, futuristic artifact number 8, which causes, among other things, a banana taken from its bunch to be returned to it and gelled.
After several experiments, the team eventually discovers they have accidentally invented a machine capable of sending messages to the past, which they later designate as "D-Mail." Okabe then learns that he is the only one capable of retaining his memories of worldlines prior to the changes made in the past; he calls this ability "Reading Steiner" after exchanging emails with John Titor, a user on @channel who claims to be a time traveler and who, according to Okabe, appeared online in 2000, although there are no current references to him. In this worldline, Titor announces that SERN will dominate the world in 2036 after completing its time machine and will deprive people of their freedom, which differs from the history Okabe remembers, in which Titor comes from 2036 to prevent the outbreak of World War III in 2015. The only element that prevails in both is the mention of the IBN 5100 to fulfill his mission.

The day is July 28, 2010. Okabe attends Dr. Nakabachi's lecture accompanied by Mayuri. Minutes before the event begins, the building is shaken from above, so Okabe goes to check the rooftop, where he sees a satellite-like machine. After making a scene against the supposed inventor of the time machine and calling his theory a rip-off of John Titor's, which he had published online 10 years earlier, he is led into the hallway by Kurisu Makise, whom he only recognizes once they are outside the room.
She asks him what he was trying to tell her about 15 minutes earlier, which confuses Okabe, since this would be the first time they've met. So instead of answering her question, he says goodbye and runs downstairs. At that moment, Okabe receives a mysterious white noise video attached to an email, which he closes when Mayuri arrives, unable to find her metal Upa, a capsule toy Okabe bought her there.
However, their meeting is interrupted by a man's agonizing scream from the floor above. Having ordered his friend to leave the building, Okabe goes to where the sound originated, finding Kurisu Makise's body lying in a pool of blood. Shocked by this, and once back on the streets with Mayuri, Okabe decides to email his friend Daru, informing him of what he had just witnessed; immediately after pressing the button to confirm the email, everyone around him vanishes, leaving both the street and the nearby shops empty.

He and Itaru are students at the Tokyo University of Electronics and have been friends for about three years, according to him, although Itaru claims their friendship was only for a year.
Okabe founded the Laboratory of Futuristic Artifacts, a small research institution located above the CRT television store. It is an area where he and his lab colleagues create "futuristic artifacts for the betterment of humanity." He refers to himself as "Laboratory 001 member" (the founder of the laboratory).
Rintaro has always been very close to laboratory member 002 and co-founder of the laboratory, his childhood friend Mayuri, to whom he made a promise to protect her when they were young.
Rintaro lives a normal life with his small group of friends until he creates the Telephone-Microwave with Itaru.

It is later revealed that his "mad scientist" persona is largely a facade he uses to make life more interesting for his dear childhood friend Mayuri. After her grandmother's death, Mayuri fell into a deep depression, but Okabe pulled her out of it by acting like a cartoon character and declaring her his hostage. He later abandons his chuunibyou facade upon witnessing Mayuri's multiple deaths, revealing a serious side to himself that he hadn't shown in the first half of the series. He works tirelessly to undo the changes caused by all the D-Mails he had sent, thus retrieving the IBN 5100 and preventing his childhood friend's death. As a result of experiencing dozens of time jumps, he becomes quite cynical, depressed, and frantic. He also develops a guilt complex, believing himself responsible for everything that happens and blaming himself whenever something goes wrong, even when he had no control over it or couldn't have foreseen it. One example is when he blamed himself for stopping Suzuha from leaving during the stormy night, which resulted in her losing her memory and failing to find IBN 5100, despite Suzuha's insistence that it was all his fault for not going straight back to 1975 instead of stopping in 2010 to find her father.
In the ending of Suzuha ("Irreversible Reboot"), Okabe's personality becomes excessively warped and twisted as a result of being forced to choose between saving Suzuha or Mayuri. Despite this, he soon reverts to his former self when confronted by Suzuha.
He appears to have developed feelings for Kurisu, as well as for Faris, Luka, and Mayuri, though these latter feelings are determined by the route chosen in the visual novel. However, he openly displays his affection for Kurisu near the end of the story, regardless of the route chosen.

Okabe is a melodramatic, eccentric, and rarely tsundere individual. He's a self-proclaimed mad scientist who likes to go by the nickname "Hououin Kyouma," and frequently uses it to introduce himself to others; most of the time, however, people don't seem to mind and instead address him by his real name or "Okarin" (a nickname Mayuri and Daru use). This makes him somewhat hypocritical due to the fact that there's literally no one he calls by their real name, and he particularly calls Kurisu by a series of names that irritate her to varying degrees.
Okabe is also socially inept, to the point that he saw absolutely nothing wrong with yelling in Kurisu's face for calling him "Okabe" instead of "Hououin Kyouma" and couldn't understand why she was crying afterward. His social skills are so poor that Kurisu actually considers Mayuri's childish attitude normal by comparison. Although he is very intelligent, Okabe is shown to be easily fooled; when Kurisu sent him a D-Mail saying he was an "airhead," he took the statement as a compliment, only to realize later that it literally meant he had a head full of air.
Okabe enjoys portraying himself as an agent working against a certain "Organization" he believes is always after him, as he thinks this image gives him a cool and mysterious aura. However, this seems to fade as the story progresses, with SERN likely replacing the "Organization's" villainous image. He generally comes across as delusional and paranoid, making strange gestures such as talking to himself on the phone and frequently engaging in fits of manic laughter; he had a severe case of chuunibyou (eighth-grade syndrome), as seen at the beginning of the series.

Okabe has the features of a lanky young man, with a square jaw and bony cheeks. He has short, black hair combed back, brown eyes, and a small amount of hair on his chin. Okabe also wears a lab coat that reaches below his knees over a plain white shirt (light gray in the anime) and khaki pants; he carries a red feather in his chest pocket and lets the end of his belt hang loose.

In the visual novel, Okabe has a "dusty" appearance. His face is pale and unshaven, and he looks much "dirtier" in contrast to his relatively "clean" appearance in the anime.