Steins;Gate: Okabe Rintarou [ENTP]

Extroverted Intuitive (Ne): Rintarou often seems delusional because he indulges his fantasies to such a great degree. He invents a whole alter ego (Hououin Kyouma) and revels in his role as a "mad scientist." Rintarou can often be seen talking to no one on his cell phone, pretending that, "the organization" is after him. When his experiments turn out to yield results, Rintarou jumps unthinkingly into the dangerous business of time travel. He often gets ahead of himself, needing Kurisu to ground him in reality. One of Rintarou's hobbies is naming things, usually using the most ridiculous references to Norse mythology. He comes up with not one, but many ways to avoid calling Kurisu by her real name, ranging from "Zombie" and "Assistant," to "Christina." Rintarou names the final world line "Steins;Gate" for no other reason other than because it sounds cool.       

Introverted Thinking (Ti): Rintarou teases his friends mercilessly. He is an expert at coming out on top in a conversation, turning people's own words back on them them. His "mad scientist" role that he creates for himself means that he acts uncaring and callous, only breaking down when people close to him get hurt. Rintarou has such a great trust in theory that he often stumbles when reality doesn't match the system in his head. (This is were Kurisu comes in) However, in the end it is Rintarou's unconventional thinking and ingenious problem solving that allows him to break the cycle and save both Mayuri and Kurisu.   

Extroverted Feeling (Fe): Rintarou has a strange way of bullying people, and then turning around and taking on all of their problems as his own. He goes to great length to help people, trying his best to fix every problem his friends might have. Rintarou accepts people as lab members easily, trying to make them feel welcome in an aloof and slightly awkward way. His "people sense" is unfortunately used selfishly quite often, making him an expert at teasing people. He knows exactly the things that will bother them the most, especially Kurisu. When Mayuri dies for the first time, Rintarou goes into an emotional spiral, trying again and again to save her life. In the end, once he has saved Mayuri, Rintarou refuses to give up and manages to save Kurisu as well. He selflessly endures a great deal of pain, just so that Kurisu doesn't have to die. 

Introverted Sensing (Si): One of the reasons that Mayuri's deaths weighs on Rintarou so heavily is that he must experience it over and over again. The fact that he might be able to save her doesn't compare to the fact that she has already dies countless times. Eventually Rintarou falls into some in the grip behavior. Before he snaps himself out of it (Literally. Time travel) he becomes fatalistic, assuming that the pattern that he has seen a thousand times will repeat itself no matter what he does.