Father: Esdeath was shown to be close to her father, as she spent her early life under his wing due to the death of her mother. It was he who she learned the philosophy of the strong survive and the weak die which moulded her mind to strongly embrace the concept. After his death, she is shown to miss him as she admitted it herself, but due to the creed she learned from him she nevertheless viewed him as a weak individual.
Tatsumi: Upon seeing Tatsumi's victory smile in a tournament she held, she instantly became deeply and genuinely in love with Tatsumi and immediately claimed him as her own. She then seeks advice from Bols on how to win Tatsumi's heart and plans to have Tatsumi fall for her using Bols' advice. Believing him to be uniquely worthy of her affection, she refuses to show romantic interest in anyone other than him, claiming he is the only one she can see as a man and is willing to do anything to protect and keep him saying that she burns with the passion to possess him completely in order to see his smile and have his feelings. She shows little concern when Tatsumi tries to convince her to join the rebellion army saying that it's understandable that people hate The Empire and that he would no longer have to worry about it as long as he remained with her, as she would not allow anything to happen to him.
When Tatsumi escaped from the Jaegers on Mount Fake, Esdeath only became more infatuated with Tatsumi, saying her desire for him was hotter now that he left. But while she said that, in the case of Tatsumi fighting the Jaegers that the Jaegers would have to fight back, she held on to the belief that Tatsumi was not that weak, and that his will to fight and survive was a wonderful thing, vowing that when they would meet again she would force all her feeling into him.
Her affections for Tatsumi also change many aspects of her cold and battle fanatic character as she even goes on what she claimed to be a night patrol but in truth she wanted to stroll because the moon looked pretty, saying that such a thing is out of her character and that it's Tatsumi's fault. Her personality also changes a great deal as she becomes incredibly loving and caring for Tatsumi, making her happier, gentle and more at ease. She even goes so far as to improve the abilities of her Teigu to the point she could freeze time and space for the sole purpose of never letting Tatsumi run away. Her love for him is to such an extent that she hesitated to fight him (in Incursio) despite all the openings he had, feeling like a part of her did not want to fight Incursio, despite not knowing that Tatsumi was inside the armor. Her kindness, however, does not get in the way of her desire for only strong fighters, as she orders her soldiers to fight back against Tatsumi if he refuses to surrender peacefully, but she did so believing that Tatsumi was not that weak and that he would survive and they would meet again. She also subjected Wave to light torture as punishment when he failed to prevent Tatsumi from escaping the Jaegers and letting a member of Night Raid escape (not knowing that the one who was inside Incursio was Tatsumi at that time).
Esdeath has also shown to be feeling down whenever Tatsumi is not present and tends to feel sad and lonely when thinking about him. She also has a book of where she drew pictures of Tatsumi that she looks at from time to time. Also, despite being a battle fanatic and smiling at the thought of more rebellions, her smile instantly faded when her thoughts turned to Tatsumi as she hoped they would meet again soon.
Even after she realized that Tatsumi was a member of Night Raid, she protected him from being violated by members of Wild Hunt, and despite all the questions she wanted to ask and have answered, she stopped caring about such things as soon as she saw Tatsumi and embraced him, saying that she missed him despite knowing that they were enemies. When attempting to get Tatsumi to join under her one last time during his imprisonment, after standing adamant against her after hearing of Lubbock's demise, she initially consigned him to die seeing as he'll never be hers. Revealing however that she never intended to execute him but fake his death sentence and whisk his body away afterwards, only growing more infatuated with him after his Teigu had evolved. Increasing his power nearly 11 fold, but she finally came to her senses after taking a gutshot from his new form knocking her out of the fight between her, Budo and the rest of Night Raid. Realizing that her feelings would never really have an effect on him plus the fact that his greatly enhanced state conveyed his resolve coupled with her underlying regret of letting affection cloud her judgment, Esdeath finally resolved she'd have no choice but to kill him the next they met but also conveyed she'd be fine dying at his hands as well.
Najenda: While viewing her former comrade as an enemy of the Empire, Esdeath still holds respect for Najenda and views her as a rival of sorts. Esdeath mentions that Najenda is an excellent general, being able to fight with a calm and burning heart.
Mine: As a rival for Tatsumi's affections the relation can be considered incredibly hostile. When first hearing that the former was going out with the unmentioned opposition, Esdeath was initially devastated by the reveal. Resolving to take him away from her by making Tatsumi her subordinate, and in failing that after prepping to execute him as Mine came bursting in; who rather brazenly stated to be the latter's beloved, filled Esdeath with amicable envy and resentment towards her. The General openly admitting how it was she could get so close him in the first place and delighted at the thought of mutilating her when the chance came.
The Three Beasts: In order to secure their loyalty, Esdeath let the trio do as they please while on missions; in Liver's case, she also offered to make all his problems "disappear". While they served under her, Esdeath would often have meals with the three, and, while walking around the Capital on her own, thought about treating them to ice cream that she found delicious. When the Three Beasts were killed, Esdeath viewed it as being natural for the weak to be destroyed by the strong, but still went and put flowers on their graves and said that she would take revenge for them.
Seryu Ubiquitous: Despite Esdeath's belief in the survival of the fittest, she still consoled Seryu after the loss of Dr. Stylish, and expressed concern over Seryu's corresponding degenerating mental health according to Wave. With Seryu's death, Esdeath was notably sorrowful, viewing it as a disappointing waste of potential.
Run: Esdeath viewed Run as "useful" both as a battle asset and as her personal aide who would do different kinds of tasks for her. After his death, Esdeath immediately swore vengeance against Wild Hunt members who were responsible for it.
The Jaegers: Though Esdeath initially showed little reaction to each member's demise, she dedicated her last battle in memory of the Jaegers (including Kurome and Wave; whom she believed to also be deceased), showing that she missed them, despite her usual, uncaring attitude toward their deaths. She also showed small acts of kindness toward each member, such as comforting Seryu, inviting Bols to join the rest of the group for dinner, taking all of them out for ice cream, et cetera.
Merraid Oarburgh: During her childhood, Esdeath had entered a professional martial arts tournament in order to test her skills where she then encountered another Merraid, who was a prodigal child fighter, and like her managed to easily defeat her competition with little to no effort despite her young age. Eventually, Esdeath was paired up with her in the final bout of the tournament where the two engaged one another in a violent duel, effectively exciting the young Esdeath due to her opponent's sheer skill and eventually causing her to desire to kill her in a serious battle. Sensing this, Merraid decided to forfeit due to sensing Esdeath's bloodlust, causing Esdeath to become visibly annoyed and angry at her opponent's cowardness.
Later Merraid approached Esdeath at her tent outside of town wanting to befriend her by sharing a meal together. After showing off their strength, Esdeath relented and allowed her to share a meal with her, happily causing her to rejoice and introduce herself. The two thus then began talking about their pasts, family businesses, chosen careers and future plans, developing somewhat of a friendship with each other. However, their talks eventually ended with Merriad attempting to make sexual advances towards Esdeath and she began lustfully groping at Esdeath by saying that she would become "stronger" through "girl love".
Esdeath, in turn, violently attacked her in retaliation and attempted to kill her by reaching for her hunting knife, but Merriad happily giggled at Esdeath's reaction and wondered if she was "going too fast" as she made her escape.
Years later, Esdeath seems to have gotten over her initial hostile view of Merriad as she happily looks back at her memories with her, as seen where she shared this story with the Three Beasts without hostility.
Syura: Despite Esdeath being the type who held no qualms killing innocent people to get what she wanted, she shows obvious disdain toward the activities of Syura and Wild Hunt for their viciously hedonistic actions toward the Empire and its citizens. Especially when one of Wild Hunt's murdered victims was Bols' Family. Later, Esdeath managed to file an official report that had forced Honest to officially disband Wild Hunt, angering Syura.