Tensei Ida/Synopsis

History
At some point before Tenya attended U.A. High, he asked his older brother what motivated him to be a Hero, to which Tensei replied that he wanted to be a 'cool' type of Hero that helps others when they are in need. When Tenya speaks of his admiration for his older brother, Tensei is joyful that Tenya looks up to him and says that he must be a great Hero since Tenya admires him.

Vigilantes Beginnings Arc
Tensei is patrolling Naruhata when he receives a backup call due to an inexplicable and sudden appearance of several Instant Villains in the city. Tensei runs to the place where the villain outbreak is taking place and together with other heroes who had also received the call, they subdue all the Instant Villains in a short space of time.

Sometime later, Tensei attends a meeting at the police station with several of the heroes who had participated in suppressing the outbreak. Once in the meeting room, Detective Tanuma informs them that the Instant Villain they had defeated, Detective Tanuma informs them that the Instant Villains they had defeated are unwilling civilians who were injected with Trigger by someone. The officer explains that the people in question were more victims than they were villains.

When the meeting ends, and Tensei prepares to return to his duties, the police station is attacked by the Suicide Bomber. Tensei and other heroes prepare to face him, but the villain is quickly defeated by Midnight and Eraser Head. After congratulating them for their work, Tensei leaves.

Some days later, Tensei and his hero agency Team Idaten are dispatched to the Naruhata district highway for reports of a runner-type villain whose Quirk is amplified by Trigger. This time, Team Idaten's PITO1 truck is chasing the running villain, and after having confirmed that there are no civilian vehicles ahead, PITO1 allows Turbo Hero "Ingenium" to chase down the running villain.

While Tensei is initially able to catch up to the villain, he fails to match with the villain's greater range of mobility, for which the villain mockingly states that the Turbo Hero must stake his life on running if he wants to catch him. The villain effortlessly avoids Tensei's attempt to subdue him and kicks him, causing Tensei to crash due to his high speed. An airbag system prevents the crash from being fatal. The villain manages to escape and disappears.

Determined to catch him next time they meet, Tense decides to jog through the streets of that part of the city to study the terrain well. During a morning jog, he meets with Koichi Haimawari who was using his Slide and Glide Quirk without permission. Tensei catches up to Koichi, which shocks him, and manages to stop Koichi from crashing.

Tensei introduces himself to Koichi as the Turbo Hero: Ingenium. Koichi is fully aware of the law preventing the use of Quirks in daily life and decides to practice early in the morning to avoid authorities, so he fears Tensei arrest him for illegally using his Quirk. Instead of arresting Koichi, Tensei takes an interest in his mobility-type Quirk and even offers him advice, apparently solving one of Koichi's biggest faults when using his Quirk. Impressed by Koichi and his Quirk, Tensei happily offers him a business card to Team Idaten, assuring him that even an unlicensed hero such as Koichi could find a place on his team.

Later, Tensei and Team Idaten are again tasked with capturing the runner-type villain, who notes that Tensei seems to be making sharper movements. Tensei made the decision earlier to sacrifice all the safety measures of his suit (much to his team's disapproval), in order to shed as much weight as possible and match the villain in his mobility. The villain believes he has successfully convinced Tensei to foolishly risk his life to keep up with him, but Tensei makes clear that he did not merely endanger himself to keep pace; instead, he is trusting that his team will keep him safe.

Tensei and his team devise a strategy in which Tensei would lure the villain into a dead-end strip of the highway, with the rest of Team Idaten ready to apprehend the villain when he falls into their trap. While Tensei is kept safe thanks to the crash pads his team laid out for him, the villain avoids the trap entirely when he reveals he has wings and the ability of flight. The villain then escapes from the highway and takes to an old part of the Higashi-Naruhata district, all while avoiding Team Idaten's coordinated attempts to corner and subdue him. Tensei remarks the difficulty of the operation is due to the town's unfamiliar layout and the villain's ability to use the shadows to his advantage.

Later in the chase, Tensei and his team unexpectedly find the villain beaten and subdued, all thanks to the efforts of the vigilantes Knuckleduster and The Crawler. The Crawler claims that being used to the old district's layout makes it easy to determine the villain's likely escape route. Seeing that their job is done, the Vigilantes retreat. A Hero of Team Idaten asks Tensei if they should chase after them. However, Tensei decides to call it a night.

The next morning, Tensei meets with Koichi again during his morning jog in order to thank him, having recognized him from the night before. Though Koichi is terrified of having his identity revealed, Tensei says that the vigilante's secret identity is safe with him. Tensei then requests the return of his business card, claiming that Koichi has already found his place as "The Crawler", and he respects him for it. Much to Koichi's dissatisfaction, he returns the card, to which Tensei makes the attempt to cheer up his jogging buddy with a friendly race.

Vs. Queen Bee Arc
While in Tokyo, Tensei and his team receive a request for help: a cat with a Quirk had taken control of a bus full of tourists and was now roaming the streets without control, so it was feared that the situation would end in a disastrous accident. Tensei decides to go ahead to help tourists.

Everyone in the bus is panicking until Ingenium comes to the rescue as he enters the bus, finding that Koichi is also one of the passengers, with his mother Shoko and his friend Makoto. They both decide to pretend they don't know each other. The driver informs him he cannot use the brake or steer the vehicle, to which the Pro Hero notices it would be difficult to stop something so big, and fears for the possibility that the bus may have crash in a urban area.

Suddenly, Knuckleduster appears in front of the vehicle, holding a large handmade cat toy to get the attention of the cat bus, and tosses it aside to make the bus divert into an express lane, and thus prevent it from crashing. Still, now they are heading to a destroyed overpass and they only have a few minutes time-limit to the hero. Team Idaten comes on its way with a truck, including their new recruit, Enigma, who uses her Quirk to transfer passengers from the uncontrolled bus to the truck. Koichi’s group are the last three people to be rescued.

Unfortunately, Kuin Hachisuka, the one responsible for the whole situation, has been watching the events, and she is not willing to make things easy for Tensei and his team, so she gives the cat a dose of Trigger, causing it to attack the truck and move away, with Makoto still on board. Right as Ingenium goes after the bus to rescue her, he starts to run out of gas. He informs his crew about this but they can’t help because the truck is out of commission as they ask for a request of someone with a mobile Quirk. Koichi decided to help under his alias as The Crawler, giving him grape juice to fill his fuel.

U.S.J. Arc
Tensei is first mentioned by his younger brother, Tenya Iida, when Ochaco Uraraka asks about his lineage. Tenya discloses that the Iida Family have been heroes for generations and asks if Ochaco or Izuku Midoriya know of the Pro-Hero Ingenium. When Izuku confirms that he is a fan of Ingenium's, Tenya reveals that the Turbo Hero is his brother. Tenya also mentions that Ingenium is a leader with dozens of sidekicks working alongside him and he wishes to become just like his older brother.

U.A. Sports Festival Arc
Tensei searches the streets of Hosu City for the Hero Killer "Stain". While ordering his sidekicks to patrol certain areas, Tensei happens to notice Stain in an alleyway and confronts him. The Hero Killer defeats and grievously injures Tensei before leaving him for dead. The police find Tensei in a pool of his own blood and take him to the Hosu General Hospital. Once there, Tensei undergoes an operation that saves his life.

After learning about what happened from their mother, Tenya eventually makes his way to see Tensei at the hospital. In spite of his injured state, Tensei apologizes to his younger brother for not being the hero he looks up to anymore. Tensei also admits that he has become paralyzed from the waist down, marking the end for the Turbo Hero "Ingenium". Tenya cries out and pleads for Ingenium not to die, so Tensei decides to pass the moniker down to his younger brother.

My Hero Academia: Two Heroes
While he does not appear in person, it is revealed that he and the rest of his family were invited to I-Expo. However, Tenya is the only one who was able to attend.

Joint Training Arc
Tenya mentions that his brother has been recovering remarkably since the Hero Killer incident. Tensei later appears in Tenya's flashback during the third round of match-ups against Class 1-B. He teaches Tenya how to improve his Quirk and make Recipro more powerful, faster, and last longer than before.