Denki is a rather shy boy and he is not able to stand up for himself. Denki says that he wants to stand up to his father so he can study and become what he wants. His personality later changes when he is bitten by a shadowy figure which causes him to try to kill the gang of boys that were bullying him. Denki soon snaps out of it and helps Boruto Uzumaki bring an end to what he has caused. Denki becomes more confident in himself after the event when he joins the Academy.
Denki is a bespectacled boy with dark eyes and black chin-length hair some of which he gathers in a top-knot, allowing the rest to fall around his face. He wears a blue suit with white trimmings, blue shorts and sandals. He is particularly small for his age, standing as the shortest of all the Academy students.
Denki is quite an intelligent boy, showing enough skill with computers that he was able to hack the Academy's security systems. As he continued his studies in the Academy, his skill for ninjutsu has gradually grown, able to effectively launch kunai at his target, and showing more noticeable agility.
He was bullied by a group of students in an alley where Boruto passed by and helped him. The two immediately became friends and Denki was inspired by Boruto to act on his own and pursue what he wants causing the former to have an argument with his father where a certain unknown shadowy figure overpowered him and "partially" controlled him. On the way to the opening ceremony of the Academy, Boruto saw Denki and followed him. He learned that Denki was planning to get his revenge from his bullies which surprised Boruto. There, Boruto saw something on Denki and thought it was peculiar. Following on the events on the train, Boruto learned that Denki was trying to collide their already defected train with another train defect. Due to Boruto's words and pursuing, Denki seemed to become aware of what he was doing, just in time of collision Boruto managed to swing the switch to move the train out of another rail and before Boruto might fell Denki saved him together with the bullies. Boruto and Denki then approached the opening ceremony using the defected train causing it to hit with the Seventh Hokage's stone face. The next day, Denki made it to the academy and seem to be friends with Sarada Uchiha and Chōchō Akimichi.
Two weeks later, after Boruto's suspension ended and he finally joined the class, Denki greeted his new friend. Soon afterwards, Boruto performance in a practice run earned him second best in the class, which Denki congratulated Boruto on. Later, while trying to have lunch together in the class room, they got into a confrontation with the class' top student Iwabee Yuino. As the rebellious older student began speaking out on his views of strength being everything to ninja and Boruto represented the worst of the students being lazy, Denki stood up for his friend. He insisted that Boruto is as driven as anyone and wants to make a name for himself. Iwabee, annoyed at Denki talking back to him, grabbed him fiercely, to which Boruto came to Denki's aid. As two students began arguing about what it means to be shinobi, they decided to skip class to settle things in fight. Denki joined the rest of the class to watch the fight in a training arena. Ultimately, Boruto and Inojin Yamanaka's respective words resonated with Iwabee, ending the fight. Despite the pleasant ending, Denki and the rest of the class were fiercely scolded later by sensei Anko Mitarashi for skipping class.
During a class introducing students to summoning techniques, Boruto's continued antics to show off, Sarada scolded him on his foolishness. This sparked an argument between all the boys and girls. Later during their lunch break, Sarada began to fight with Boruto over who would get the last yakisoba bun. Shino appeared, insisting that they boys and girls settle things with a race challenge for a flag. The challenge quickly got heated. Denki used his computer skills to hack the Academy's security system but ultimately Denki was captured by the girls. In the end contest ended with the girls getting the flag. Despite their victory, the girls made peace with the boys after working together to save Chōchō from falling off the roof.
Later, the class gained a new transfer student from Otogakure named Mitsuki. Wanting the students to warm up to Mitsuki, Shino organised a welcoming party for the new student. When Shino's efforts for the party backfired with his insects, the class began to freak out, with Denki begging someone to make the insects go away, which Mitsuki did with his Wind Release: Breakthrough, causing even more damage to the Academy.
Later, the class was assigned by Shino to split into groups of three and each tail a different workplace for a few days to better understand non-shinobi life. Denki joined Iwabee in gong to the fireworks factory. While simple at first, Iwabee's over-eagerness caused several fireworks to go off. After learning that some of their friends were hospitalised and checking on them, Denki and Iwabee were soon recruited by Shikadai to help stop the culprit. They met up with their friends at the post office to discuss their plan. After leaving to patrol the village, the culprit attacked the empty post office, unleashing the spectre on the post chief Komame. However, Denki's team anticipated this, realising that they were being spied on before and corned the masked culprit. While half the group pursued the culprit, Denki's half stayed to save the possessed Komame. While ultimately saving the post chief, the spectre and culprit ultimately got away.
When another attack came, the area was closed off. Denki, along with Inojin and Shikadai, wondered where Boruto was, along with the missing Sumire. The following morning, they found Boruto, along with Sumire and Mitsuki in the field. They were soon joined by Sai and his unit, who took Sumire in for question. As Denki asked what happened, Boruto happily brushed it off, saying everything was fine.
Several weeks later, Shino decided to change up the three-man teams for their next challenge to determine the optimum pairings for graduation, where Iwabee insisted to team up with Denki. The following day, Inojin told his friends that his father has gathered files on Academies in other villages, making Denki wonder if Sumire was going to leave the Academy. During the challenges, Shino was then called aside concerning Sumire. As the class began discussing rumours that Sumire was being transferred to a different school, they were relieved to see her return to their class.
When the class began learning the Tree Climbing Practice, Denki was the only one in the class unable to effectively perform it. Worried that he would have to repeat the class as it was key to passing the year's final exam, a distraught Denki unintentionally compared himself to Iwabee's reputation. While Denki was ashamed of his statement, Iwabee merely brushed it off. As his friends tried to give him tips to better handle the skill of chakra-induced climbing, they explanations only further confused him. Metal offered to help Denki improve his focus and strength with cliff-climbing. During which, Denki met Metal's father Rock Lee, who was moved by Denki's determination and gave him a jumpsuit, insisting it would help. Later, Iwabee approached Denki. Not wanting Denki to be left behind like he was, Iwabee gave him better pointers on the climbing skill. As Denki began improving, he noticed that Iwabee was still struggling with his general school studies. The two then proceeded to tutor each other. On the day of the final exam, the two came across a burning building with children trapped inside. The two used their climbing skills to get inside and save the kids. Despite arriving too late for the test, Shino was moved by how effectively they used their climbing skills to save people, deciding to still pass them.
- Denki's name, when written as 電気, means "electricity". His last name, literally meaning "Lightning Gate", most likely comes from one of two gates locating in Asakusa, Tokyo, Japan.