The Schnee Dust Company is owned by Winter's family. Winter herself does not work for the company, though she visits the SDC World Headquarters on the day Weiss calls for information in "A Minor Hiccup".
It is confirmed in "Punished" that Winter's title as heiress to her father's company was revoked upon her decision to join the military.
Winter is a member of the Atlesian Military. She is a member of the military's Special Operatives unit, and Qrow accordingly refers to her as a Specialist. She is also a subordinate of General Ironwood, whom she addresses as "sir".
Winter trained Weiss at least once prior to Weiss' fight against the Arma Gigas. She told her sister that she had to become stronger if she wanted to leave.
Although initially cold to Weiss, Winter has genuine concern for her sister's well-being, inquiring about her social life and eating habits, rather than just her studies and class rank. However, her methods of demonstrating this affection are rather unusual, rebuking her sister for misinterpreting her previously-mentioned inquiries and proceeding to slap her on the head for it.
She also knows of her sister neglecting their father, and can sympathize with the situation. She tells Weiss that if she wants to explore Remnant and learn about herself then she cannot answer to their father. She gives Weiss one last hug before departing.
After she and Weiss reunited in Atlas, she expressed relief to see Weiss again. As she continued to criticize Weiss for her actions and methods of re-entering Atlas, Weiss embraced her in a heartwarming hug before Winter hugs her back.
In "Sparks", she entrusts Weiss to keep her secret about her becoming the next host for the Winter Maiden powers after Fria passes away.
In "With Friends Like These", after Winter along with Penny heard Ruby's warning about Ironwood's plan to abandon Mantle, she doesn't seems to care or worry about Weiss being one of the most wanted list and only focus on her mission to obtain the Winter Maiden powers.
In "The Enemy of Trust", after Penny obtains the power of the Winter Maiden, Winter's relationship with Weiss becomes strained, she suggests Weiss and her friends to surrender and turn themselves in and comply with General Ironwood's orders. When Weiss refuses to go along with his plans, Winter tells them that they should run.
Weiss, seeing how badly Winter is injured, refuses to leave her sister behind and tries to argue for her to stay with her and run away with them and later states her refusal to leave her like that. Winter in turn emotionally replies that Weiss wasn't leaving her, rather she was giving her a head start before proceeding to call for Atlas medical assistance and back up to help capture Team RWBY. Showing although Winter loves and cares for Weiss deeply, her loyalty to Ironwood would always come first for her and she would even comply with his orders to capture Weiss when the order is given, but due to her love for her sister, Winter can not go through with it without at least giving her a chance.
Weiss, seeing the resolve in her sister's eyes, calmly wished Winter luck in her chosen path and choice, before leaving to pursue her own.
Not much is known about Winter's relationship with her father, but it is implied that at some point it was a strained one. The extent of this compared to her sister's is unknown. During her conversation with Weiss, she mentions how she had been financially cut off from their father as well, then recalls her amusement towards their father's reaction the day Weiss left for Beacon. It is also hinted that their father was not pleased with Winter's decision to join the Atlesian Military when she graduated from Atlas.
When Weiss admits that their father cut off her access to his credit card, Winter gives two options as advice. One is to call him, beg for his money back and try explaining once more why she chose to study at Beacon. Winter's tone of voice hints that the conversation would likely be heated and needless. The other option is for Weiss to continue as she has been, exploring Remnant and learning more about the world and herself. This option indicates that Winter is not opposed to Weiss being independent of their father.
Both Winter mentioning seeing their father's face the day Weiss left, and her awareness of Weiss' repeated attempts to explain why she wanted to go to Beacon indicate that Winter is still in communication with him. It remains unclear how frequently they communicate or how well they get along.
In "Pomp and Circumstance", she intentionally arrives late to avoid seeing her father after Weiss confronts him with her team.
In "Sparks", she is shocked about her father temporarily shutting down all nonessential SDC operations in Mantle until he's elected for the council and comments that their father has found a spark to set the Kingdom on fire.
In "Cordially Invited", Winter's negative relationship with her father is fully shown in her outburst toward him, after becoming increasingly annoyed and angry while he manipulates and controls the Council's meeting with Ironwood. She shouts at her father that he cannot simply buy trust like he buys everything else. Jacques then twisted her words for his own argument, leaving Winter upset and flustered. She attempts to defend herself, but Ironwood stops her, and she feels the need to exit the room and calm down.
In "As Above, So Below", where Jacques' actions in illegally wining the Council Elections was revealed, Winter had aimed a clear hostile look of disappointment at her father for the depths he would go to to win and later expressed contempt for him due his ignorance for inadvertently giving Arthur Watts his high level clearance into the Atlas systems and giving him the chance to run rampant and create mass chaos all over Mantle.
Weiss has stated that her and her sister's younger brother dislikes Winter; however, Whitley claims to have a strong sense of respect for her.
Winter's exact relationship with her mother is unknown, as she has largely separated herself from her parents. She is likely aware of her mother's alcoholism and depression, having taken on a somewhat maternal role for her sister Weiss in their mother's place.
Ironwood is Winter's superior in the Atlesian Military. As such, she has great respect for Ironwood and follows his every order almost without question. Ironwood appears to reciprocate this respect, as he considers Winter one of his best when arguing with her father.
Ironwood later reveals the full extent of his trust towards in Winter during the events of "Sparks" where it was revealed that Ironwood had long since selected Winter to be the inheritor and successor to the powers of the Winter Maiden and informed her the truth regarding Salem and the Relics and the ongoing shadow war being waged against her, showing that Winter is one of his most trusted lieutenants in his endeavors and is privy to many of the General's activities.
In "With Friends Like These", after Ruby's warning about Ironwood's plan, she seems shocked and disturbed about this, but she is willing to follow his plans to kill Fria and take the Winter Maiden powers, defending his actions as making the hard choices for the rest of the world.
In "The Enemy of Trust", after Penny obtains the Winter Maiden powers, she still refuses to betray Ironwood because she would rather stay loyal to him than abandon him and help her sister.
In "New Challengers...", Qrow eagerly waits for her arrival at the local bar, explaining to the bartender that the fight he was there for has finally arrived. This prompts him to head over to Beacon Academy, in an attempt to catch up with her. It is revealed that Winter appear to be previously acquainted with Qrow, as she is on first name basis with him, with the latter often amusing himself at the former's expense. During their meet up in "It's Brawl in the Family", Qrow decapitates the AK-200s that accompanied Winter to Beacon. This culminates a battle in the middle of Beacon Academy's courtyard. Although it is shown during their battle that they have no malicious intent towards each other and that this is simply their way of teasing one another. Upon close inspection, the two are seen to be smirking at each other throughout the altercation.
After they reunited in Atlas, Winter questions Qrow's chaperoning methods as to which he replies that "it's hard to change the mind of the kids when they have their minds set on something."
It is revealed in "Sparks" that the only reason why Qrow wanted Ironwood to dismiss Winter from The Inner Circle's meeting was because he did not want her getting involved with their dangerous mission to stop Salem. Though, at the time, he was still not aware that she was already in the know regarding The Maidens and The Relics and was in fact Ironwood's primary candidate to be the next Winter Maiden.
During the February 2019 Update of the mobile game RWBY: Amity Arena, Qrow was given a Valentine's Outfit named "Dandy Qrow". A year later, during the February 2020 Update, Winter was given a matching Valentine's Outfit named "Queen Winter" with the following caption: "Now Winter can fight with Qrow all day as mortal frenemies!". Additionally, the player title "Mortal Frenemies" is distributed to the players who logged in during that year's Valentine's Day.
Winter appears to think little of Ruby upon initially meeting her, stating that she is "appropriately underwhelming". She is, however, thankful to Ruby for "taking an interest" in Weiss. In the conflict between Winter and Qrow, Ruby sides with her uncle.
Fria is the current Winter Maiden. After the fall of Beacon, Ironwood gives Winter a secret assignment: to be Fria's only caretaker until her passing. In "Sparks", Winter has a good relationship with Fria, as they are seen having a nice cup of tea. As such, Winter is the only person Fria's allowed to see, meaning that Winter will become her successor once Fria passes away.
Winter and Penny share a professional yet good relationship with each other along with both of them are some of the people Ironwood told the secrets of the Maiden powers, the Relics and Salem. In "Cordially Invited", Winter and Penny have a heart to heart on the topic of emotions, and whether to hide them. Penny is unable to recognize why the Schnee Manor causes Winter to feel intense anger, nor why she chooses to hide her emotions away. In "With Friends Like These", Winter and Penny talk about Ironwood declaring martial law, and his decision to sacrifice Mantle to Salem, with Winter defending the general's actions over making the hard choices for others.
In "The Enemy of Trust", Penny saves a falling Winter who got hit by Cinder's attack who then explains that saving her was unnecessary since "her [Winter's] life did not matter", to which Penny respectfully disagrees to. After the battle, their relationship turns sour once Penny takes the Maiden's powers, effectively robbing Winter of what she saw as her destiny, and betraying Ironwood to Ruby's Group. Winter reports the Maiden powers are gone to Ironwood.
Winter is shown to have a disdain towards Cinder, whereas Cinder sees Winter in low regard, accusing her of being a puppet to Ironwood. In their fight, Cinder begins to rant at Winter, fully showing her contempt for the Atlas specialist and deeming her to be no better than the other selfish, self-centered and greedy Atlas elite who believe that as long as they have all the power they could keep it forever as she violently attacked her and venting her frustration and refusal to "starve".
During their fight and Cinder's subsequent attempt to obtain the power of the Winter Maiden from the dying Fria, Winter manages to slash off Cinder's Shadow Hand right before she could reach the elderly Maiden, causing Cinder intense pain and sending her into a violent rage after regrowing her limb, causing the angered Maiden to begun venting her anger and frustrations at the Huntress by brutally throwing her weapons at her and begins slowly maiming and injuring the Huntress gradually before finally injuring her to the point of rendering her incapable of defending herself as Cinder prepares to stab her to death. However before Cinder could finish her off, she was stopped by the recently ascended Penny and later forced to retreat by Ruby's arrival.