Hiroko is Yasuhiro's mother and the person who is the closest to him, resulting in her being kidnapped as Hiro's captive for the first motive of the Killing School Life. The two never interact directly in Ultra Despair Girls due to Yasuhiro never finding the adults' Resistance secret base during his time in Towa City. Hiroko loves her son more than anyone else and is very protective of him. She mentions that she is very proud of him and calls him successful, sharp, handsome, tall and kind. She calls him perfect, but "teeny, eentsy bit clumsy with money", which bugs her a little bit. She also admits that he's had big problems with school and women, but she finds his flaws rather cute in a way.
In one event of Ultimate Talent Development Plan, Yasuhiro calls out for his mom to save him from Tenko Chabashira.
In one event of Danganronpa S: Ultimate Summer Camp, Hiroko gives Yasuhiro his "lucky Ganesh" which he had forgotten at home. She says she'll give him the real thing back at home. Yasuhiro happily says that's his mom, knowing him best. Hiroko mentions that she can't remember the last time they went on a vacation together, and is happy that they're able to go on one, and that they'll always keep these memories. Yasuhiro agrees, but he's a little embarrassed that he's the only legal adult in their class and his mom is with him.
In an interaction with Monokuma, he suggests that Yasuhiro grew up the way he did because Hiroko was too easy on him, which Hiroko becomes angered and insulted by. In another event with Kyoko, Hiroko implies that she may want help with Yasuhiro's debt from a detective such as Kyoko or Shuichi. Talking with Makoto makes Hiroko relieved that Yasuhiro has friends, as he's never had that many before, and especially considering how he is older than the others due to him repeating grades. Hiroko is also worried that Yasuhiro is so laid-back that he has no sense of danger, but she supposes that could still be a strong point of his.
At the Summer Festival, Hiroko can check on Yasuhiro and tell him to go be with his friends and celebrate instead of being by himself. She says that times like these make the best memories, but Yasuhiro says that's why he's with her. Yasuhiro says he's wanted to have a drink with her ever since he became of age, but he never got the chance. But since they have the time now, Yasuhiro brings out some sake and the two drink together. If Hiroko talked to Monomi instead, Monomi assumes Hiroko wants to know about Yasuhiro's grades, and she ends up telling stories about him to Hiroko.
At the bonfire, Hiroko notices Yasuhiro sitting out of the dance, and says he should get involved. Yasuhiro doesn't like the idea of a folk dance in front of his mom, though, but would be more open to breakdancing. Hiroko doesn't see how Yasuhiro could breakdance with all that hair of his, and Yasuhiro says he's thinking of doing a makeover. Hiroko teases that Yasuhiro's way to young for a makeover, but gives all the power to him, and Yasuhiro shares his determination to show that she will like his new look.
After the end of the camp, Hiroko thinks that it's almost unfair that she got to have front row seats in watching her son's growth.
- “Little older than you two. Proud of him, a very successful boy. He's a sharp boy. Handsome, tall, kind... If he didn't come out of me, I wouldn't believe he was my own kid! But even if my son *is* perfect, something has been bugging me... It's just a small thing, but... He's just a teeny, eentsy bit clumsy with money. He's in debt. Oh, and he also repeated middle and high school about 4 times. Oh yeah, and he's also just terrible with women... Well, those flaws are kinda cute too, in a way.”
- — Hiroko Hagakure about her son after Komaru and Toko give her her Hit List Target entry.
The ship started with the release of Danganronpa Another Episode: Ultra Despair Girls. According to TV Tropes , before the English translation, it wasn't originally clear for the non-Japanese fans how exactly the two were related. Knowing that Yasuhiro was 21 when he entered Hope's Peak Academy and that Hiroko doesn't look anything like him and looks about the same age as him, there were rumors that the two were married to each other. The English translation eventually revealed that the two are a mother and a son. This resulted in everyone abandoning the romantic ship between the two and switching to a familyship instead. According to "Abandon Shipping" trope on the game's YMMV page on TV Tropes, there was even some porn created that the reveal made the fans not proud of.
- Despite the fact that she says in-game her age is a secret, a page in the art book shows Hiroko's beta designs states that she is "approximately 36" years old. Considering her son's age, that means he was born to Hiroko when she was only around 14 years old.
- The family used to include Hiroko's husband before he divorced her.