Her grandparents, being deceased, do not have any more development in the story. That being said Shirayuki has talked about her grandparents from time to time. They owned a pub, and were the ones to raise her after her mother died, and her father disappeared. It is said that Shirayuki loved them very much, and that they were good people. They are very much responsible for Shirayuki being who she is and raised her in a fashion to be able to support herself.
Shirayuki first met Zen when she was on the run from Prince Raji and was just waking up from her nap outside of an abandoned house. He had tripped over a wall that he was jumping over, and when she had offered to help patch up his arm, he had refused, accusing her of possibly poisoning him, to which she proves wrong as she hits herself with his sword, then applying medicine to. At first she doesn't know he is a prince, not until he confronts Prince Raji and comes to her rescue. They begin as very good friends who inspire each other to work harder and achieve more, and later on throughout the series her feelings of respect and friendship transform into love. When Zen confessed his love to Shirayuki, she didn't know how to answer him. She loved Zen, but she didn't know how to say it. Later in the story, she confessed her love to Zen and they became a couple. She comes to rely on him for his advice and protection, something that she has never done before, as she has been raised to be a naturally independent person. In return, Shirayuki wants to protect his name, and encourage him to be the best that he can be. As of chapter 60, they are in a long distance relationship.
In the beginning of the story, Shirayuki dislikes Raji because he is a shameful, idiotic prince and is the reason she fled Tanbarun. In the first chapter, he sends a guard to go tell her that she was to be his "concubine", as he found her apple-red hair to be "rare and unusual". As an act of defiance against the spoiled prince, Shirayuki cuts her hair short and leaves her ponytail behind for Raji's soldiers to find, symbolizing that while he can have her hair, he can never have her. Later on, he tries to poison her with an apple with the intention of immobilizing her, allowing him to take her back to the castle. However, Zen ends up being poisoned, and out of concern for her new friend, Shirayuki decides to face Raji in order to get the antidote. In the end, Zen intimidates and threatens Prince Raji into swearing that he would never try to see Shirayuki again. Later, Shirayuki and Raji attempt to redefine their relationship, despite getting off to such a horrible start. Throughout the series, they slowly become friends with each other. Beginning with helping him when his stomach pain and smiling back at him when he said something nice, she is later the only person in history to receive the title "Friend to Tanbarun Royal Family". This title is later the key to her attending royal gatherings.
Even though she has a healthy respect for him, Shirayuki's relationship with the Izana Wistaria is quite strained in the beginning. They have not had much interaction but have had multiple private talks about herself and Zen. After the incident at Lyrias, Izana's attitude has slightly changed about her, seemingly to trust her a little bit more. He continues to test the relationship of Zen and Shirayuki, so much so that he tells Shirayuki she must go to a city in the kingdom of Clarines to help a breakout in a sickness, and that she must stay there for 3 months without Zen.
When she first met Obi, he had been hired by Lord Haruka to intimidate Shirayuki into staying away from Zen and to frighten her away from Wistal castle. When Obi is discovered by Zen, he begins working for him, and slowly befriends the rest of the group. In later chapters Zen orders Obi to be Shirayuki's guard while she is in danger and this has allowed them to become good friends. Shirayuki sees him as a strong but friendly person, who is a bit odd. Nevertheless she respects his abilities and values his friendship dearly. Obi refers to her now as "Mistress" and has romantic feelings for Shirayuki, but does not act on them out of respect for her and Zen.
Ryuu is a very smart but very antisocial 12 year old who works as one of the chief herbalist who becomes in charge of Shirayuki. He first meets the protagonist Shirayuki in an herb garden at first their relationship seems very strange because he seemed a bit on the shy side but he soon begins to open up to her and feel frightened and worries when she started to cry. Many people in the castle are frightened by him due to his mysterious nature and his knack and interest in poisonous herbs. He soon becomes a little brother figure to Obi who takes him under his wings and teaches him how to climb in return Ryuu teaches him about herbs.
She first met him along with Kiki and Zen. As Zen explains that he always loses to Kiki at chess. Mitsuhide is fatherly to Shirayuki, giving her advice about Zen and encouraging her when times are tough. They seem to have a very close friendship.
Kiki is a good friend to Shirayuki. Kiki is the only girl besides Shirayuki herself in the main group. They usually talk when they have a room together. Kiki usually has Shirayuki's back and sometimes gives advice about Zen to her. Like Mitsuhide, she also has a very close friendship with her.