Naofumi Iwatani/Relationships

Raphtalia
Naofumi's first slave, a Tanuki demi-human child, that he purchased from the Slave merchant. Naofumi was forced to purchase her as a slave early on in order to compensate for his lack of offensive abilities, along with the stigma of the false charges against him that prevented him from forming a party with anyone else. Naofumi initially chose Raphtalia for her low price, and because he wanted to imagine enslaving Malty, who trumped up the false charges against him. Despite his questionable motives for obtaining her, Naofumi becomes a naturally benevolent master, and treats Raphtalia well after acquiring her. He provides her with medicine when she is ill, food when she is hungry, and protects her from harm during battles. Although she is a slave to him, the only times he would ever activate the Slave Crest to prompt an action was when she was too frightened to perform the action on her own. He also provides her with adequate shelter, and comforts her during her various night terrors.

Raphtalia physically matures rapidly from a child to a young adult within a week or two due to the affects of her level grinding. Raphtalia becomes significantly more outgoing towards Naofumi and even has a decent handle on him, carefully findings ways to get him to comply with her choices despite their master-slave relationship. She becomes a much needed pillar of support for him throughout their time together. When the 3 Heroes, along with the King and Malty attempt to sabotage Naofumi's ability to accel by forcibly removing the master-slave relationship between him and Raphtalia, she rebels against her new status as a free woman, and willingly chooses to remain in a master-slave relationship with him.

She's the first person, after Oyaji, to take his side after what Malty did to him, and the one who ultimately succeeds in bringing him out of his despair. She want’s Naofumi to look at her as an adult woman, and has on at least one occasion stripped completely naked in front of him to get his opinion of her naked body. Unfortunately for Raphtalia, Naofumi misses her point completely, as he knows that she is really only a ten-year-old, despite the physical appearance of a twenty-year-old, and thus doesn't think of her feelings as romantic.

Naofumi constantly expresses a father-daughter relationship with her, but Raphtalia would very much beg to differ. She is the one that Naofumi trusts and ultimately cares for the most of his companions. Raphtalia is also the only reliable restraint against Naofumi's more villainous tendencies, and she expresses to him her preference that he act as a proper hero, despite his belief that he is not. Whenever Naofumi takes pleasure in the suffering of those who've caused him grief, especially Malty and Trash, Raphtalia tries to reign him in and cautions against expressing his joy.

For Naofumi Raphtalia is a reliable partner, she saved him from his hatred from being betrayed by Malty, and is his most loyal follower. She is the friend with whom they shared their joys and sorrows together.

Filo
Naofumi's second real comrade and slave. He purchased her as an egg from the same slave trader that he obtained Raphtalia from. Although she was purchased more along the lines of a beast, he raises her with compassion alongside Raphtalia. Like the phenomenon of level grinding that Naofumi experienced with Raphtalia, Filo quickly grows beyond a normal Filolial and is later revealed to be an extremely rare Filolial Queen. This allows her to later demonstrate an ability to assume human form with the appearance of a youthful girl. Filo is far more direct with expressing her impulsive nature, which at some instances has been encouraged by Naofumi when he finds it amusing to him and negatively impacting those he views have wronged him. For example, when she kicks Motoyasu in the crotch during her first encounter with him, Naofumi immediately feels she was a brilliant investment and tells her to do it every time henceforth. Generally speaking Naofumi has found Filo's expression of selfishness, gluttony, and childish-tantrum behavior to be annoying, but despite this he still cares for her greatly as a companion. The second time he was able to invoke his Shield of Anger, since the time that Raphtalia was nearly taken away from him, was directly caused by his assumption that Filo had died.

Melty Melromarc
The Second Princess, and younger sister to Malty, whom initially believed her sister's lies about Naofumi and expressed hatred for him (In WN). She attempted to force Naofumi into apologizing for dishonoring her Father and amend the relationship between them, but was treated by him as an annoyance in return. After the Three Heroes Church attempted to kill her due to a trumped up conspiracy, Naofumi became the only person that Melty can actually rely on to save her life as the other heroes, her sister, and her knights are all either being deceived by the Church, or are willing participants in the conspiracy. She has become something of a Tsundere towards Naofumi, due to these events, and it's implied that her feelings for him extend beyond what she wants him to hear about. She dislikes being treated by him as a child or being called "second-princess" by him, and eventually convinces him to call her by name instead.

Rishia
Recruited to Naofumi's party after being kicked out of Itsuki's party. She was framed for breaking one of Itsuki's accessories by another member of the Itsuki's party, and Itsuki being a willing participant of it after Rishia inadvertently stole the spotlight that he wanted during a clash with Glass, and the heroes from another world. Naofumi empathized with Rishia and felt a mutual connection due to his similar situation for being framed of false charges. After Filo saved Rishia, Naofumi swore to her that he would help to make her stronger so that Itsuki would beg to have her back on his team. As she spent time within Naofumi's village, she gained confidence and immense fighting skills. Rishia doesn't share the negative view of Church of Three Heroes because of her education at Faubley, an expresses fear at Naofumi's demeanor until Raphtalia was able to remove her doubts. She respects Naofumi and aids him.

Amaki Ren
Like the other heroes, Ren was initially led to believe Naofumi was guilty of the charge of raping Malty; however, he was also, alongside Itsuki, one of the only people to defend Naofumi when Malty cheated to allow Motoyasu to beat him in their duel. He was grateful for clearing up the epidemics in a village which was caused because of his actions. He is also the only one of the heroes to actually believe Naofumi after he is charged later with the kidnapping of Princess Melty. While it can be said Naofumi does not find him as unbearable as Motoyasu or Itsuki, he still displays petty dislike of him and even tried to kill him when he succumbed to the influence of his Curse Series weapons(in WN). He does however see Ren's good side as a hero, and defends him when criticized by Raphtalia's high standards.

Kawasumi Itsuki
Naofumi's relationship with Itsuki is strained to put it politely. He dislikes how Itsuki actions are driven with the sole purpose of flaunting his pride and showing off for applause. He begrudges Itsuki, along with the other heroes, for believing Malty's frame up of Naofumi, and their subsequent treatment of him afterwards. Although Itsuki did stand for Naofumi during the rigged duel and rebuked funds; Naofumi felt that it was more to satisfy his ego and not really a genuine attempt. Later on, Naofumi defended Itsuki from Raphtalia's criticisms by stating that Itsuki was stuck up, but would never let harm befall his allies. Naofumi's attitude changes when he loses what little respect he had for Itsuki after he finds out that Itsuki kicks Rishia out of his party under the pretense of a crime which he and other party members orchestrated against her.

Kitamura Motoyasu
Initially Naofumi believed Motoyasu played a part in framing him for raping Malty, but over time has come to realize that Motoyasu is very naive, delusional, stupid and evidently doesn't know he's being manipulated by Malty. It was Motoyasu nearly taking Raphtalia away from him through a rigged duel which finally set Naofumi off enough to awaken the Shield of Wrath. Motoyasu tries to behave in a friendly manner towards Naofumi, despite the charges placed on him, but becomes something of a rival to him, especially with Malty's continued influence upon him. Once Naofumi's name is cleared he begins to show more of a kind side towards him, but refuses to accept it when he's told that Malty is the one who set him up. After Malty finally betrays him as well, Motoyasu completely breaks, falls completely in love(or lust) with Filo, and starts calling Naofumi, Father in Law. He becomes even easier for Naofumi to manipulate, and all but swears loyalty to him.

Aultcray Melromarc XXXII (Trash)
Naofumi hates the King, and with good reason; as he played a part along with his daughter Malty, of setting Naofumi up with the criminal charge of rape, and made certain to spread the word all throughout the kingdom. Although, given the King's genuine display of stupidity in believing the claims that Naofumi could brainwash people, it's likely he may have just believed Malty's claims and acted upon them rashly. Ultimately, the King hates the Hero of the Shield, and that just unfortunately transferred to Naofumi because of that relationship.

When the Queen returned and cleared Naofumi's name, she allowed him to mete out a punishment to the King, Naofumi immediately asked for the death penalty, but was talked down to a less extreme punishment that resulted in changing the King's given name to "Trash". Trash was subsequently stripped of all his rights to the throne along with any power he had already accrued within the kingdom. Trash's unreasonable hatred for Naofumi continued after this until he witnessed Atlas, who closely resembled his long-lost sister, under Naofumi's care. After this, Trash resigned himself to remain silent in front of Naofumi, unlike previously when he would create a ruckus against him. Later on his wife, in her dying breath, requested that he bury his petty hatreds and join hands with Naofumi to fight for the future, but he was unable to do anything at the time other than dwell within his remorse. After receiving advice from the spirit of cane, Naofumi began to act out like a bad character in order to awaken the sleeping wisdom within Trash. They were finally able to make amends between the two of them, and were able to work together to fight off the threat of their enemies. While Naofumi didn't forgive Trash, he accepted to move forward while Trash would beg for his forgiveness and began to treat Naofumi in the same manner as his late wife would.

Malty Melromarc (Bitch/Witch)
Naofumi hates Malty for setting him up for the crime of raping her when he first appeared as the Shield Hero. This hatred grows exponentially over the series as Malty continually antagonizes him and actively tries to add to the misery she'd already brought into his life. Because of Malty's actions, Naofumi's ability to trust anyone that is not bound by a slave to him is extremely limited to a few individuals. After Malty's mother, the Queen, returns and clears Naofumi's name, she stripped Malty of her right to inherit the throne as punishment for her actions. Naofumi immediately stated that Melty should be executed, but was convinced to merely renaming her "Bitch" which would later turn into "Witch" instead. Malty remains utterly unrepentant for her past actions and aims to do whatever she can to get back at Naofumi.

Glass
Glass seems to consider Naofumi and his party to be worthy opponents, even asking for his name after he manages to force her to retreat during their battle(for reference, she moments before defeated the other three heroes and their respective parties, all of which are groups larger than Naofumi's party, at the same time). Like many others she finds some clear fault with Naofumi's personality.

Mirelia Q Melromarc
The Queen and Naofumi are on fairly good terms as business acquaintances. While he knows he's being used by her, he also knows that she needs him, so he's willing to put up with it. The fact that she cleared his name and punished her husband and daughter for their mistreatment of him seems to be the crux of their relationship. Both of them treat each others as equals, but she does acknowledge his worth both politically and as a hero. She tries to push her second daughter into a marriage with him at every possible occasion.

Elhart
He runs a weapon shop in Melromarc, and is the only person who believed in Naofumi after he was falsely accused by Bitch. He made most, if not all, of the equipment worn by Naofumi along with his carriage, and is also responsible for teaching Raphtalia the basics of Swordsmanship. His skills come from a blacksmith from the East. He wants Naofumi to find another blacksmith as he believes his skill to be sub-par, but Naofumi places higher value on his skill and his friendship.

Slave Merchant
While Naofumi considers the Slave Merchant to be a useful person due to his role in providing him with various slaves for his growing army, he does not indicate any real trust for the man. The merchant has noted that Naofumi has good business sense, and is not an easy man to deceive, and refers to Naofumi as his favorite customer. Naofumi on the other hand creeps out on the slave merchant.