Kirishima and Midoriya get along well. They seem to be very supportive of each other, often seen encouraging one another.
Kirishima was the first to encourage All Might to stop the fight between Midoriya and Bakugou in episode 7, worrying for Midoriya's safety. He repeatedly expressed concern for Midoriya throughout the fight. He enthusiastically introduced himself when Midoriya returned from recovery.
When Midoriya choose to give Tenya Iida his title as class representative, Kirishima supported his decision because he trusted Midoriya's judgement.
Kirishima demonstrates his care for Izuku once again after the latter was immobilized from helping All Might against Nomu. He ran toward Midoriya, asking if he was okay.
When Todoroki approached Midoriya before the Sports Festival began, Kirishima stepped in to ease the confrontation. He also thought Midoriya was being too hard on himself when Midoriya stated that Todoroki is more capable than most, encouraging him not to talk so negatively.
Midoriya commended Kirishima's quirk while watching the fight between Kirishima and Bakugou. He was surprised by Kirishima being able to get close enough to put Bakugou in a defensive position. He labels Kirishima's quirk as "simple but effective" (episode 24).
In episode 31, it's revealed that Kirishima reported the text Midoriya sent his friends about the fight in Hosu. Midoriya wrote him back, and Kirishima was willing to risk getting in trouble with Fourth Kind to reply.
When he and Bakugou arrived at the pool, Kirishima said that he received Midoriya's message, implying that Midoriya was the one to invite them.
Kirishima appears to understand Midoriya's feelings to an extent; he knew how Midoriya must have felt when they weren't able to save Bakugou. He's the one who reached out to convince Midoriya that they could go rescue Bakugou. Once the rest of the class left, he backtracked a little, concerned that Midoriya's injuries might prevent him from being able to leave.
Midoriya seemed concerned about Kirishima buying such expensive night vision goggles, but Kirishima brushed it off. He also asks if Kirishima was okay after being startled by seeing so many Nomu in the building they were spying on. When Midoriya returned from being under house arrest, he promised to work hard to catch up, and Kirishima encouraged him. Kirishima applauded him again on his plan during the students' fight with Togata.
Kirishima supported Midoryia while rescuing Eri and late rwhen getting him to return to U.A. He saved Midoryia and Iida from their fall and showed respect to Midoryia for trying to rescue Bakugo from the Sludge Villain. He then cried at Ochaco's speech to defend Midoryia and helped the other boys bathe Midoryia.
My Hero Academia: Two Heroes
- Midoriya called out in alarm when Kirishima was about to be hit by a villain's quirk.
- Kirishima, alongside Iida and Mineta, cheered for Midoriya when Midoriya and All Might went up against Wolfram.
- Kirishima praises Midoriya's quirk while putting down his own. Midoriya sees the full potential and usefulness of Kirishima's quirk and thinks it's cool/awesome.
- Kirishima seemed disappointed about missing the start of the match between Midoriya and Todoroki.
- While in disguise, Kirishima gave Midoriya advice on how to better fit the role of his character.
KiriDeku is the rival ship of KiriBaku and BakuDeku, while KiriDekuBaku allows both Izuku and Eijiro to be shipped with Katsuki Bakugou in a polyship. Fans love how their personalities match, and how it's an energetic and optimistic person with a more shy and reserved one. Due to their closeness, it has over 2112+ works on AO3. While it isn't a naturally popular ship, considering the popularity of KiriBaku and BakuDeku, a few TodoBaku shippers tend to like KiriDeku and see them going on double dates. Still, some appear to prefer their relationship as platonic.
- Main article: KiriDeku/Gallery
- Midoriya thinks Kirishima is cool, while Kirishima admires Midoriya.
- Bakugou Rescue Squad refers to the ship between the two, Shoto Todoroki, Momo Yaoyorozu and Tenya Iida
- Ghost Hunting Squad refers to the ship between the two, Shoto Todoroki, Hanta Sero and Tetsutetsu Tetsutetsu
- KiriDekuBaku refers to the ship between the two and Katsuki Bakugou
- ShinTodoBakuKiriDeku refers to the ship between the two, Hitoshi Shinso, Shoto Todoroki and Katsuki Bakugou
- TodoBakuKiriDeku refers to the ship between the two, Shoto Todoroki and Katsuki Bakugou
- TodoDekuKiri refers to the ship between the two and Shoto Todoroki
- TodoKiriShinBakuDekuraka refers to the ship between the two, Shoto Todoroki, Hitoshi Shinso, Katsuki Bakugou and Ochako Uraraka