Hiyori and Yato have gotten closer throughout the series. Despite the fact Yato should be helping Hiyori with her soul leaking issue, Hiyori also helps him out on more than one occasion. While she acts more serious than him, the two are quirky and help on their dreams, no matter how childish or difficult are. Yato cares for her greatly, and when being told that cutting his ties with her could solve her problem, he is reluctant, but it appears he is willing to do it to help her, only for Hiyori to refuse. Yato eventually offers guidance to Hiyori when she's unsure about her academic future and whether she should become a doctor and inherit her family's hospital. After receiving his small shrine from Hiyori, where he vowed, albeit in a state of inebriation, that he will make Hiyori the happiest girl in the world and puts a lot of faith on her, just she has put hers on him. Hiyori is the one to save him from Izanami after saying his "real" name. When Hiyori was about to turn into an Ayakashi in the Hospital Arc, Hiyori asks Yato to kill her to save the rest, but he refuses to do so because she has a precious life with people who care deeply about her.
Romantic feelings have been hinted between the two, but mainly from Yato, who stalks her, knows several private facts such as her bra size, where she hides her book of martial arts and also her yaoi manga, etc, and has declared as her future husband. During his and Ebisu's encounter with Izanami that his image of Izanami is Hiyori, and Ebisu says that the goddess is seen differently by each person, taking the form of the person they are most comfortable with (note that Izanami was actually a mixture of Hiyori and Sakura). During the matchmaking ceremony, Kofuku playfully ties his and Hiyori's plaques together, hinting at a potential romantic relationship. However, it's stated that any match Kofuku makes usually ends in misfortune and disaster, so this may be an indication of future hardships between them.
As of Chapter 79, it has been confirmed that Yato does have feelings for Hiyori.
As of Chapter 78, it has been confirmed that Hiyori does have feelings for Yato.
Yatori is canon but they think the other one doesn't love them back and are depressed.
When first introduced, Yukine is rather cold towards Yato and seems to enjoy putting Yato down. Yato says that Yukine is "even better" as Yukine, often referring to his relationship with Yukine as that of a father and son's, calling him "my child", "atonement" and his "joy and pride", often bragging his accomplishments to other gods. As Yukine continues to sting Yato and cause problems for him, he refuses to get rid of Yukine and puts up with the pain, until Daikoku steps in to punish Yukine. Hiyori states that Yato is like a father to Yukine and that he had done so much for him, putting up with his sins and blights and he didn't want to let him go, greatly affecting him. This may relate to how Yukine had his own issues with his father so the fact Yato acted like a father had a profound effect on him. After that, Yukine becomes less cold to Yato, showing more loyalty and care to his master while still teasing him. This was shown especially when Yukine sacrificed himself to save Yato from Bishamon resulting in Yukine become a Blessed Vessel. It was only a rare honour to protect the sacred ship, even to the loyal Shinki who wanted to put his name.
However, it is known that there are still some minor battles because of some misconceptions about not telling the true name of Nora or Yato. After Yato tells Yukine about the past and everything about his father, he vows to help Yato to never kill anyone again and help him become the God of Fortune by killing any cataclysm before it strikes. To do this, Yukine is very strict against Yato and plans daily routines of killing at least 100 phantoms, so he gives up spending money with his lucky charms. He wants to be grateful to him (as Yato has pointed out) and to be successful as a Fortune God, although he is still pretty sweet to Yato. Yukine's number one priority is his master's safety, and this implies that the only way to protect Yato is to be ready to let Bishamon die.
Kofuku is Yato’s trusted and equally mischievous god friend, despite being introduced as his girlfriend. This trust is displayed when Yato tells Hiyori to come to Kofuku should anything happen to him. Kofuku supports Yato throughout the story; this support ranges from actively aiding battles, using her ability to create phantom vents that serve as an escape mechanism for Yato, to more passive support activities such as letting Yato and his Shinki crash at her house or betting against him in tough situations (which, as a goddess of poverty, increases Yato’s luck).
They first met each other when Daikoku approached the Calamity God to ask him to sever his ties between him and Daigo. After Yato did so, he thanked him and said he would forever be in his favour. Daikoku can be a little rough with Yato sometimes. He doesn't like it when Yato is too close to Kofuku or when he's crashing over at their house doing nothing. Yato playfully calls him "Mom" while acting like a freeloader son. Despite their antics, they're actually very close friends. During Yomi arc, Kazuma refers to Daikoku as Yato's "best friend". He was also one of the Shinki to attend Yato's purification ceremony when Yukine had to be punished.
Sakura was Yato's first true Shinki. Yato first met Sakura under a cherry blossom tree when she asked Yato to give her a name and learned about her human past, something he didn't experience with Nora. Their short relationship was a happy and life-changing experience for Yato, which ended abruptly when she transformed into a Karma Ayakashi. Sakura showed the young Yato a different path of life than the one given by his father. Yato's "name", the goal to become a God of Fortune and current personality is because of his time with Sakura. Overall, she could be seen to have served as a motherly figure for him. Yato still mourns her death every spring when the cherry blossom trees bloom.
Bishamon has a hate for the other God of War Yato, seeking revenge for Yato killing her Shinkis. She has spent decades hunting him, always desiring to end him and anyone who happens to be acquainted with him. Her hatred of him drives her to be reckless and rash on many occasions. After the truth behind the slaughter of the Ma clan is made known to her, she lets go of her grudge against him, albeit the two still have a rocky relationship. She reveals that the cause of her hatred toward Yato is that such an unknown God like him saved her life twice and she feels guilty for not being able to save two of her Shinki clans. While the two still exchange barbs and punches with each other, they are more civil and have even worked to attain common goals, even bragging about their Shinkis to each other. Some tensions reemerge when she learns Yato is related to the sorcerer that caused both Ebisu and Tsuguha's death, but she has referred to him as one of her few allies against Father. Yato has recently gone so far as to talk back against the Heavens to protect her, showing he does care for her as a friend despite their rivalry. Yato refers to her as "psycho bitch" ("crazy chick" in the anime), but also as his "drinking buddy".
Kazuma sees Yato as his benefactor due to the fact that Kazuma requested Yato to kill the Ma clan to prevent Bishamon from dying, sparking Bishamonten's vendetta against Yato. Ever since, Kazuma has felt indebted to Yato for saving his master, doing things like supporting his strange antics or attending Yukine's purification, all of it behind Bishamon's back. The fact that Kazuma was willing to risk his precious relationship with Bishamon for this proves how much Kazuma appreciates Yato. In chapter 58, Yato refers to Kazuma as his benefactor for taking care of him over the years just as how Kazuma referred to him as his benefactor by killing the Ma clan. Yato also defends Kazuma's attempt to forcefully solicit information from Yukine by saying he was only doing it to protect Bishamon.
Mayu is Yato's previous Shinki before Yukine. While she served under Yato, her name was Tomone and she took the form of a small dagger. Mayu often complains about Yato and about how miserable she was when she lived with him. Now serving Tenjin, Mayu is still a valuable ally for Yato and also risked her life to purify Yukine to save him.
Tenjin is a famous God of Fortune who has many shrines over the country. While homeless, Yato sometimes sleeps in Tenjin's shrines to stay safe from phantoms since shrines are sacred grounds. Tenjin likes to tease Yato and his way of living, often bragging about how much money and worshippers he has compared to him. Nonetheless, he does give Yato jobs so that he can earn some money, even though Yato claims it's just stupid jobs he doesn't want to do himself. He has also helped Yato on a few occasions, the most significant case is when he allowed Yato to use his shrine to access Takamagahara to rescue Hiyori when she was kidnapped by Kugaha.
Yato first met the God of Fortune Ebisu when he asked Yato to sell Yukine to him because he was interested in getting a Blessed Regalia. He even suggested sharing Yukine, implying that he became a stray. Yukine ended up rejecting the offer after he became Yato's guidepost. Afterwards, the two met once again when Nora told Yato that Father wanted him to save Ebisu from the underworld. Because of this, Yato became Ebisu's bodyguard of sorts in the Underworld. There, Ebisu told him that he believed Yato could be the kind of God that could bring happiness to other people, inspiring Yato to become a God of Fortune. Likewise, Yato inspired Ebisu to value his own life and his present incarnation, instead of throwing many of his lives away to attain a goal. Even though their time together was short, their new friendship was enough to prompt Yato to decide to save Ebisu because he wanted to, and not because his father told him so.
After Ebisu reincarnates, Yato is at first apprehensive of the new Ebisu and tells him to go away. However, he later takes him to the Olive Ken, a restaurant the previous Ebisu frequented. The two remain close throughout the series, frequently meeting to discuss current matters. Yato is often very protective of little Ebisu, making sure his shoes are always tied so that he doesn't trip or that he values his life over his goals. He doesn't want to betray his trust, so he is honest regarding the topic of his father. Despite Ebisu's young age, Yato confides some of his insecurities to him, who in turn gives him advice when Yato has some identity crisis in his new path as a God of Fortune.
Yato is one of the many gods who has made Nora their Shinki, calling her Hiiro only when necessary. They have the same "father", whom Yato has served in his early years. It is not known if Yato is the first god to claim her as Shinki, but it is shown that the two have long been together since Yato was still a child and deeply cared for her well-being. They "played" together by killing many people and Shinki before he changed his attitude, then being forced by their father to kill others with her. Nora was also the Shinki Yato used in killing the "ma" clan of Shinki claimed by Bishamon.
Even when he has Yukine, he still uses Nora, which causes some tension between the two. She claims to care for Yato and saved his life several times, but ultimately disregards his feelings and frequently toys with his mind by saying how he should cut ties with Yukine and Hiyori since she is more useful and how human bonds are weak so people will forget him. She has even sicked Ayakashi on him as a way of punishing him. Yato thanked her for everything but doesn't like working with her anymore and even stated he much prefers working with Yukine. Later on, Yato finally releases her from being his Shinki.
Father is the one who acted as a father to Yato, creating the god through his wishes. He often ordered him and Nora to kill several humans and bring back their ears, which Yato was happy to do because Father praised him for his actions. Father seems to view Yato as a tool and does not care for his feelings, as he told Yato to tell Sakura the God's greatest secret to turn her into an Ayakashi and kill her because she was changing Yato into a kinder person who began to think twice about his killing. It is even shown that he used to beat up and abuse Yato in the past but Yato is incapable of doing anything against him. Father has lived for several years through divine possession and it is through him that Yato is still alive because if a God is forgotten they die and Father is the only human who has been able to remember Yato for several years. He also frequently gives Yato jobs to do which involve mass murder, causing him to disappear for long periods of time, worrying for his friends.
Father enjoys teasing Yato as shown when he teased about kissing Hiyori, much to Yato's chagrin. He does not care for Yato's feelings and puts him on tests to see how much he would rebel against him, trying to sever his relations with other people, threatening Hiyori and manipulating phantoms to attack her family's hospital, causing everyone to go on a rampage and bombarding her family with lawsuits. Yato wishes to be free of Father's control but fears that should he end Father's life that he himself will cease to exist. He despises his father for the way he uses him to kill people and fulfil his means but has no choice but to conceal his identity lest he loses his "lifeline". Despite their time together, Yato doesn't know why his father decided to use the masks or disappeared along with Nora.
Takemikazuchi was the one who murdered Ebisu, so Yato is not happy at all to see him. Takemikazuchi loves to ridicule Yato and pretend he doesn't exist but is shown to be extremely jealous because Yato has a blessed Shinki but not himself, especially since his lead Shinki Kiun is extremely hesitant with the idea of becoming one. He even humiliated Yato and Yukine by making them bow during the banquet, something disgraceful for a God and his Shinki to do. He tried to spark a fight with Yato but Yukine erected a shield and proved to be superior. Takemikazuchi's desire for a blessed Shinki also comes from his role as a war God and his love for battles and disregard for people's lives, especially since he couldn't imagine how strong Kiun would be if he was a blessed Shinki since he is already one of the strongest Shinki of heaven, but still lost to Kazuma who was only a nail in the beginning. He seems to want to make an enemy of Yato since he recognizes Yato as a powerful enemy and in order to have a blessed Shinki one needs a powerful enemy. The fact that he is related to Nora and by extension Father further complicates and foreshadows the strong possibility of him being a powerful enemy in the future. This is later on proven true when he orders Kiun to ignore the search for Bishamonten in order to fight Yato.
Like with Takemikazuchi, Yato does not like Kiun because he murdered Ebisu. This is made evident when Kiun comes to ask if Yato is on heaven's side, saying no because of what they did to Ebisu. Despite wanting to be a God, he openly states how much doesn't like heaven and how he might even rebel against them including the main goddess. When Kiun tells Yato if he rejects that his status as a God will be removed and his shrine taken away and how he will be reduced to a cult leader though, Yato quickly changes his mind, much to Yukine's Hiyori's and Ebisu's annoyance. Despite this, it is evident the two still do not trust each other and Yato makes sure to keep his guard up with both Takemikazuchi and Kiun. It is clear he will be enemies with both of them in the near future.