Fuyumi Todoroki/Relationships

Enji Todoroki
When she was born, Endeavor was mildly disappointed she only inherited her mother's Quirk, but was content with her and Toya.

As with her brothers Toya and Natsuo, Endeavor neglected her in her childhood and didn't want to use her as his successor. Despite this, Fuyumi is the only child who is mostly able to look past their father's faults and forgive him for his previous behavior, especially since her father is trying to atone for his mistakes and be a better person.

Fuyumi is more than aware of how messed up her family turned out because of Endeavor's abuse, and while she expresses some fear of him, she nonetheless is the one who supports Enji the most in his effort to improve and fix his family issues. She is surprised to hear that he regularly visits her mother and listened to her voice his inner troubles. She was even horrified to watch the report of Hood defeating him but cheered on his persistence.

Her attempt at a family get-together following Endeavor's battle against Hood was what she expected to be a chance for Shoto and Natsuo to try to start a dialogue with their father, although it did not end too well due to Natsuo's animosity towards Enji. Fuyumi told Shoto she was quite hopeful and proactive with getting her father and siblings to mend relations with each other because of his recent progress.

Fuyumi’s more positive opinion of her father was likely due to the fact that she still remembered his more positive side during her early childhood with her older brother Toya prior to the births of her younger brothers, a time where Todoroki family had a much healthier relationship with each other.

She tries again months later with another family dinner, in which she also invites Izuku and Katsuki, although the outcome was not much better. Fuyumi confided in Shoto that she feel some resentment towards Endeavor but wants to move past it, for the future.

Although her initiatives have not yet been very successful, Enji thanks his daughter for all the support she has given him, thinking that Fuyumi doesn't know how much he has been saved by her.

When he leaves with the boys, he once more thanks Fuyumi for her actions who only responds to his gratitude with a smile. Endeavor later revealed that he is building a new house for the siblings and their mother, while he remains at their house alone.

When visiting her father at the hospital after her older brother's broadcast, Fuyumi was concerned and asked her father why he was crying. She was taken aback by his apologizing. After reminiscing of Toya and the events that made him become a villain, Fuyumi stated that she had a role in Toya's descent into villainy because of her fear at not saying anything. She offers to be there with the rest of the family to help her father stop Dabi.

During Toya's rampage, Fuyumi came to help her father, despite suffering several burns. After Shoto was able to stop Toya, Endeavor proceeded to apologize to her for putting so much work on her shoulders.

Rei Todoroki
Like her brothers Natsuo and Shoto, Fuyumi visits her mother for time to time in the hospital. The two appear to have a positive relationship.

Fuyumi cares for her mother physical condition, as it could be seen when she brought her a set of warmer clothes, but especially emotionally, reprimanding her brother Natsuo to mention her father in front of her, even though they had agreed not to.

In spite of the latter, she is surprised to learn that her father has visited Rei several times, although at the moment they have not seen each other face to face.

Toya Todoroki
From the little that is known of her relationship with Toya, Fuyumi seemed to have a good relationship with him when they were kids, as they used to play together. She also attempted to stop from his reckless training because he often got burned but he would shrug off her concern.

Nowadays, Fuyumi mourns his "death" and she prays at his altar. Unlike Natsuo, she does not seem to blame their father for his death.

When Dabi revealed himself in public in an attempt to attack Endeavor and Hawks, Fuyumi appeared greatly shocked by this despite not knowing his true identity around that time. After Dabi revealed his true identity as Toya, she was ultimately saddened to learn that her older brother has become a villain.

During the Final War, Fuyumi is reunited with him after a decade and didn't hesitate to rush towards the battle between both her father and her brother, despite knowing that it's dangerous. She then proceeds to reason with the latter, telling him to stop, for she couldn't bare to lose anyone anymore.

Natsuo Todoroki
Fuyumi has a good relationship with her younger brother Natsuo, and as with Toya, they usually played together as kids. The pair still get along in their older years, with Fuyumi regularly teasing him in their visit to their mother, much to his dismay.

However, unlike him, Fuyumi is able to look past their father's faults. She also wishes for him to see that she is trying so hard to fix the family that Endeavor broke, and that everyone can live together as a real and normal family. While Natsuo doesn't agree, for Fuyumi's sake, he is willing to begrudgingly participate when which his father is present, to respect the feelings of his sister, although this inevitably generates tension and Natsuo usually leaves to avoid more problems.

She also expressed concern for him after he was attacked by a villain, to which Natsuo assured her that he was fine.

Shoto Todoroki
Fuyumi and Shoto get along, they appear close enough for him to tell her that he was visiting their mother, something she was concerned about.

When he arrived home late after the Kamino Incident, she scolded him because of the dangers of going out and directed him to their raging father.

During the Pro Hero Arc, she spent time with him and Natsuo before they watched as the latter told off their father for his previous treatment to him and his siblings. Fuyumi became upset, telling Shoto of her desire of being a real family, something he sympathized with. Fuyumi watched him expressed a similar desire of seeing the man Endeavor will be.

Fuyumi is aware of the difficulties that Shoto has in relating to other people, so she is glad to know that his brother has friends in U.A. High School. During the Endeavor Agency Arc, she decides to invite everyone to a dinner to meet them. After a dinner, she once again confided in him after the dinner was turbulent. Shoto was grateful to her for her intentions.

During the Final War Arc, Shoto saves her and the rest of the family from Toya's destructive rampage.

Izuku Midoriya & Katsuki Bakugo
Eager to meet Shoto's friends, Fuyumi invite Izuku and Katsuki to dinner at Todoroki Abode with her family. At all times she is kind to them and both praise her cooking skills. However, dinner does not end as she would have liked due to the tension between her brother Natsuo and her father Enji. While talking with his brother Shoto about the matter, she is criticized by Katsuki to talk about their family drama in front of them, for it was ruining the evening, to which she apologizes, while Izuku voices his thoughts on that Shoto is a very kind person waiting for the right moment to forgive his father.

After dinner, Fuyumi says goodbye to them and she thanks Izuku for being Shoto's friend.