Taichi Yaegashi

is a member of the Student Cultural Society and the series' main male protagonist. He attends the same homeroom as Iori and Inaba and is a pro wrestling fanatic. In class, he is a fairly quiet character, always calm and inconspicuous.

Personality
Taichi is depicted as a generally selfless and considerate individual. He will go to great lengths trying to help others even if it comes at his own expense or has no direct benefit to him. This trait has earned him the title "Selfless Freak" by Inaba. He is a fan of pro wrestling, and has a lot of respect for pro wrestling jobbers.

Taichi has also proven to be a very patient man; rarely ever getting worked up and always trying to understand the viewpoints of others rather than starting an argument. Of course, he is certainly not above throwing in a few smart remarks, but tries his best not to antagonize others. Taichi is also an honest and hardworking student. He is shown to be one of the more studious StuCS members and he never chooses to copy homework as he finds it to be counterproductive and a bad habit. Taichi is also a doting older brother to his sister, Rina, and, to his frustration, he is often accused of being a siscon/lolicon.

Taichi is very fond of his friends and, in Asu Random I, he is shown to be afraid of losing his memories of the StuCS and the phenomenons to Record Deletion. This causes him to become obsessively paranoid of losing his memories and even leads him to consider abandoning his classmates who have become trapped in the Isolation Dimension in order to ensure the personal safety of the StuCS.

In  Yume Random, Taichi states he wishes to "save the world" in the future and chooses to take Science courses. "Saving the world" entails trying to solve problems like energy crisis, malnutrition, and environmental changes. By his third year, Taichi decides to attend the same university as Inaba and plans on studying biological science.

Key Problem
Unable to bear watching other people suffer, Taichi has stated he would rather endure the hardships of others in their place if he could. Taichi's obsession with being selfless is to the point where he has expressed a willingness to throw away his own life just to help another. Inaba has likened the severity of this trait to that of mental insanity.

In Yume Random, Taichi's obsession resurfaces when he chooses to use the power Heartseed gave him to try to help as many people as he can. When Inaba asks him who he is living for, Taichi states he is living for everyone else, disturbing her. Later, his desire to help backfires when he accidentally gives a couple the wrong advice. Taichi soon realizes that his obsession with being selfless has completely consumed his life and has caused him to lose sight of who he is.

Appearance
Taichi is a young man of average height, though noticeably shorter than Aoki. He has short brown hair and brown eyes, and normally displays a calm face. Aoki suggests that Taichi is quite handsome and he would be popular if he were more cheerful. Taichi is usually seen in his school uniform.

Background History
Taichi originally wanted to join a "Professional Wrestling Research Club," however, it did not have enough members interested in it. As a result, the school placed him in the Student Cultural Society. Even while in the StuCS, Taichi frequently tries to enthuse his friends about pro wrestling, though he is often met with disdain from Inaba, who labels him a "Pro Wrestling Otaku."

Taichi was a part of his middle school's Baseball Club, and was quite athletically fit. However, according to Yui, by Hito Random, he has stopped practicing.

Family

 * Yaegashi Rina: Taichi’s younger sister. The two are shown to be quite close and Rina often pesters Taichi about his love life. Despite her age, Rina is usually the one to give relationship advice to Taichi rather than the other way around. In place of their actual father, who is always away for work, Taichi acts as a sort of father figure to Rina, taking care of her, scolding her when necessary, and reminding her to do her chores. Taichi has also proven to be very protective of his sister and initially did not want Rina to meet the rest of the StuCS, though she would later end up thoroughly getting to know each of them regardless. After learning the truth about Heartseed and the phenomenons, Rina apologizes to Taichi, finally understanding the hardships her brother has kept hidden from her.
 * Mother: Taichi's mother takes care of him and Rina alone due to his father working away from home. Taichi's mother is, herself, away during most of the day due to work and relegates most responsibilities, including the caretaking of Rina, to Taichi. Inaba suggests that Taichi's mother is neglectful of her family, but Taichi denies such an accusation. In Asu Random, his mother failed to notice anything strange about him until Rina said something. She initially blamed his strange behavior on puberty and typical teenager issues.
 * Father: Taichi's father is often away on business trips, leaving Taichi and Rina alone at home often.

Friends

 * Nagase Iori: A female classmate of Taichi's, and the president of the StuCS. Admiring her expressiveness, Taichi harbors romantic feelings for Iori and confessed his love to her. Believing that Iori was going to die, they kiss while she was borrowing Inaba’s body. Their relationship never fully develops due to the constant complications brought on by each phenomenon and Iori ultimately rejects his confession after realizing their love was too premature. The two remain close friends and Iori constantly teases Taichi about his awkwardness with romance.
 * Inaba Himeko: A female classmate, and the vice president of the StuCS. Taichi helps Inaba overcome her insecurities by revealing one of his deepest secrets to her. Over the course of the series, Taichi and Inaba develop a strong bond of trust and need for one another; Taichi helping Inaba with her self-esteem and Inaba helping keep Taichi's "Selfless Freak" tendencies in check. After the class trip, Inaba reveals to Taichi that she has fallen in love with him, but he turns her down as he is still in love with Iori. Despite the rejection, Inaba refuses to give up on Taichi and at the end of the Michi Random arc, Taichi and Inaba begin dating. Inaba, even while dating Taichi, is quite violent towards him, frequently hitting Taichi anytime he says something stupid or makes a smart remark. After a confession from Taichi's side and subsequently getting back together after their breakup in Yume Random, Inaba has largely mellowed out. In Step Time, Iori compares the two to a married couple rather than dating high schoolers. During the opening ceremony of their third year, Taichi finally calls Inaba by her first name, "Himeko." Taichi promised to call her "Himeko" from then on, but occasionally forgets, which earns Taichi a flick to his forehead. In Precious Time, Taichi teams up with Inaba for the Couples Battle Royale. The two later decide to attend the same university after they graduate.
 * Aoki Yoshifumi: A fellow StuCS club member, and Taichi’s best friend. The two often share adult videos with one another and Taichi is the only club member who abstains from teasing Aoki. Though they act as emotional supports for each other, Aoki admits to being jealous of how Taichi is better than him at helping other people, particularly Yui. In Precious Time, when the StuCS came over to Taichi's house, they couldn't find any adult videos in Taichi's room and Aoki claims that Taichi hasn't borrowed any from him in a while. Aoki is misunderstood to have feelings for Taichi by Nishino Nana  and Rina, which he immediately denies.
 * Kiriyama Yui: A female member of the StuCS club. Taichi helps Yui get on the path towards overcoming her fear of men and the two develop a strong friendship. Yui later considers Taichi her most trusted male friend. In Yume Random, Taichi and Yui work together, using Dream Perception to help as many people as they can. During this time, one of the biggest feats they are credited with is contributing to the "Love Boom" amongst their classmates and helping encourage relationships.
 * Fujishima Maiko: Taichi’s class representative. Due to Inaba's intervention, Fujishima considers Taichi a bitter rival in her fight for Iori's affections. Despite their supposed rivalry, Fujishima still cares enough for Taichi to offer friendly advice from time to time. By Asu Random II, she admits that Taichi is her friend.
 * Gotou Ryuuzen: Taichi's homeroom teacher and club advisor for the StuCS. The two are shown to get along well, though Gotou will occassionally take advantage of Taichi's selflessness. Taichi is the only StuCS that gives Gotou any respect, and every once in a while, Gotou will share a few words of wisdom with Taichi. As revealed in a Drama CD, Gotou is jealous of how seemingly popular Taichi is with girls and threatens to mark his grades down out of spite.
 * Watase Shingo: A male classmate and friend of Taichi's. Taichi later learns that Watase has a crush on Fujishima and was asked by Watase to help him get close to her. In Asu Random II, Taichi promised Watase that, once they leave the Isolation Dimension, he will help Watase get closer to Fujishima in exchange for having faith in him.
 * Enjouji Shino: A female underclassman and fellow member of the StuCS. Shino has a fetish for Taichi's voice and goes crazy when he says even the simplest of phrases. eg. "Do your best" in Nise Random. He often feels insulted when Shino says when everything but his voice was unimportant. Shino has expressed a desire to be Taichi's younger sibling just so she can continue hearing his voice for the rest of her life.
 * Uwa Chihiro: Taichi's underclassmen and fellow member of the StuCS. Although initially at odds with each other, further aggravated when Taichi learns what he did to Inaba in Nise Random, Taichi later decides to forgive Chihiro. Chihiro comes to respect Taichi as a reliable figure and frequently goes to him for advice throughout Yume Random. Chihiro continues to feel guilty for the hardships he has put Taichi through, but Taichi insists he does not blame Chihiro. They are said to be similar by Iori because they both enjoy making smart remarks.

Others

 * Heartseed: Of all the StuCS members, Heartseed seems to take particular interest in Taichi. In the Yume Random arc, Heartseed personally tells Taichi that the two of them are more similar than he thinks.

Trivia

 * According to Yui, Taichi is bad at smiling.
 * Taichi is a big fan of pro wrestling, seeing it as the art of enduring physical pain and greatly respects "jobbers": wrestlers who normally throw fights to raise their opponent's popularity.  Moreover, this reflects his personality, as he'd rather endure pain himself rather than see other people suffer.
 * Taichi's favorite food is curry.
 * Twice in the series when Taichi was standing at the edge of a cliff, another character thought he was going to jump because he was depressed.
 * With the exception of Chihiro and Shino, Taichi refers to everyone by their last names.
 * Taichi is infamously bad at Rock-Paper-Scissors. However, he finally wins a Rock-Paper-Scissors match against Sone during the Couples Battle Royale after receiving advice from Inaba.
 * Not mentioned in the anime, the other members of the StuCS frequently accuse Taichi of being a lolicon.