Godou and Erica have a very complicated relationship from the very beginning. When the two first met, neither of them liked each other that much at first due to varies of misunderstanding and Erica uptight nature. But after Godou keep putting himself in danger for others or troublesome situation to help Erica out, Erica soon fall madly in love with him after getting to know him for a few months. Soon afterward, Erica has declared herself to be his lover, wife, and one true love, and Godou argues against this at every chance. However, he has privately admitted to himself that he does find Erica very attractive, and that there seems to be an connection between them, but finds her drive off-putting, as he knows if he gives even an inch, he will be wrapped up and all but married to her in no time and believed she is rushing things too fast for him. He 'does' get frustrated by her claims which many take at face value, believing the two to have already been intimate. Despite Godou tends to running away from her, he has said it to himself that she is one of his most precious persons in the world despite his claim to not rank the girls. In the end, Godou found himself falling for Erica even to a point where he couldn't live without her due to her undying loyalty and love she shows for him, making Godou aware that she meant every word she said and sacrifice a lot for him. Godou even became very open to admittedly to care and love Erica, even freely kissing her whenever he wants to. By the end of the series, Godou became more willing to engage in intimate moments with Erica and even had sex with her.
At first, Yuri thought Godou was a fearsome tyrant because of her previous interactions with a Campione and the rumors of him being a lewd person who attract women everywhere without care. Despite her fears, she still attempted to convince Godou to be more modest in his actions with Erica despite it being the other away around. Godou, at first, thought that she was very cute, but can be very pushy and hard to tell whether she was angry or shy. However, after Godou saved Yuri from the Campione Voban, the two relationship had gotten better and Yuri started to see that most of the lewd actions were on Erica. As the two interacted, Godou discovered he relates well with Yuri for being one of the normal girls and understand her greatly and help support her job as a Hime-Miko, which lead to Yuri to fall in love with Godou, though she is not yet willing to admit it, possibly even to herself. In Volume 5 Yuri has admitted that she has feelings for him, even willing to offer her purity in the future and in Volume 7 she swore allegiance for life to Kusanagi Godou until one of them dies, showing how much she looks up to Godou and how much she trust him to keep her safe and not betray her love for him. Like the other girls, Godou does not rank Yuri from best to worse but does hold Yuri in a special place within his heart and deeply cares for her. Out of the four girls, Godou tried his hardest to be gentler with her whenever they need to perform the ritual. As the series goes on, Godou began to become bolder at the ritual with Yuri who, despite disliking lewd activities, began to accept him even more. By the end of the series, Godou became more willing to engage in intimate moments with Yuri and even had sex with her.
Liliana is Godou's trusted knight. She tries to convince Godou and herself that most of the things she does for him are because she is his first knight and therefore responsibility falls to her given the circumstances. Both of them are shown to have feelings for each other and by Volume 18 Chapter 10, it is revealed that they are both aware of their feelings for each other, but under pretext of lord and knight, although they are dating like a lover. They were even willing to spend the night together if it wasn't for Liliana maid living in her house. Out of all the girls, Godou appears to trust Liliana the most for her loyal and honest nature, and that Godou entrusts her, alongside Erica, to help build up the Round Table while Godou is away. By the end of the series, Godou became more willing to engage in intimate moments with Liliana and even had sex with her.
Godou, at first, thought Ena was a troublesome woman due to Ena attempting to kill Erica to be with Godou. However, after learning she is Yuri childhood friend, Godou went out of his way to save her from the out of control Ame no Murakumo no Tsurugi. After saving her, Ena soon ends up falling for Godou for real and after apologizing for her action, Godou forgives her. While Godou see her as a friend, Ena said that she wants to be Godou's lover, and if possible, his wife. She always says that she is Godou's woman which causes misunderstandings among varies of people. However, deep down, Godou finds Ena to be very cute and a very beautiful woman, especially when she gets shy after doing something intimate with him. While Godou find her too easy going in varies of situation, Godou still trusts her enough to defend his friends and treasure her companionship. By the end of the series, Godou became more willing to engage in intimate moments with Ena and even had sex with her.
Shizuka is Godou's sister and the one person he truly fears. Godou greatly loves his little sister, but tend to find her a bit possessive and controlling at times. Shizuka sometimes acts as if she is the elder sibling and Godou is the foolish younger brother due to always making food for him and making sure he does not get in trouble. Despite this, Godou deeply care about his sister and want Shizuka to look up to him and try to be a good role model.
Ichirou is Godou grandfather and the source of his lady-killing charms. While growing up, Godou thought of his grandfather as nothing but trouble due to always worrying his grandmother for his flirting nature (despite being faithful to her) and taking Godou everywhere around the world and believe he lost him on purpose so he could learn to better defend himself. Despite his low-opinion of him, Godou does see Ichirou as a brilliant man in his research.
Chiyo is Godou late grandmother who he miss at times. Godou barely mention her, but does show signs of respecting her wishes as he went to Italy in Ichirou place because he knows Chiyo desire for Ichirou to never meet Lucretia Zola.
Genzou is Godou father. Godou and Genzou are barely seen together, but Godou does not have a high opinion of his father due to his father intense jealousy of his son bond with Shizuka and his charm with the females. Godou rarely sees him because of his work oversea and being divorced.
Mayo is Godou mother. Godou and Mayo are barely seen together, but Godou does not have a high opinion of his mother due to her "high queen" personality and her desire for many males attention and going out partying.
Originally, Hikari simply wanted Godou to start a relationship with her sister, Hikari, to not only increase their household strength but to make her sister happy. However, after being rescued from the Monkey King by the hands of Godou, Hikari developed a strong feeling towards him and defend him whenever the girls scold him. While Godou view on Hikari romantic is unclear, he does, however, care for her deeply and went out of his way to save her from the Monkey King and comfort her whenever she felt trouble.
Lucretia is Godou mentor and self-proclaim "local wife." While Godou does find her strong and forceful personality a bit off-putting, he does admit, however, to find her extremely beautiful and hard to resist.
Godou finds Salvatore to be an idiot, often calling him 'Idiot Doni' and always refused that Salvatore is his best friend. On the other hand, Salvatore finds Godou to be interesting, he's willing to lend the 'Book in Praise of David's Great Works' to Erica just so that it can protect Godou better. Salvatore declared Godou as his 'Eternal Rival' despite Godou thinks of him as one of the stupidest people in the world, but does agree how powerful he can be and did get into a silly eating contest with him. According to Erica in the last side story chapter, Godou dislike for Doni came from his resembles his father.
Originally enemies, or perhaps opponents, Luo Hao has adopted Godou as a younger brother and has vowed to teach him how to be a Campione. There are some indications that she's romantically interested in him as well.
Godou likes her well enough but thinks that she's as crazy, as dangerous, and as stupid Salvatore in her own way.
Godou dislikes Voban, but acknowledges he's a dangerous person, like a wild wolf. Voban hates Godou as well, for thwarting his will.
She helps Godou in different ways to fight Sun Wukong and as she keeps seeing Godou fight she feels respect for him. Annie which is John Pluto Smith's daily life develops a romantic interest in Godou seeing him as a hero of sorts.
Godou first met Verethragna during the event of Volume 3 where he ended up befriending him as they competed against each other in various games and sports. When Verethragna regained his Authorities and his personality changed, Godou felt responsible for the change in the youth he befriended and decided that he can't leave him alone. This is something that leads in him to battle Verethragna with the help of Melqart and the power of Prometheus' Grimoire and eventually resulted in Godou becoming a Campione by killing him. Even when the two battled each other, they still see each other as friends and at time, Godou has shown some sign of missing him.
At first, Athena thought of Godou as an enemy and gave him a 'keep out of my way' attitude. After finding out her plan to envelop the world in darkness, the two became true enemies, but Godou was willing to be merciful to her.
After Godou defeats Athena, Athena seems to have adopted a 'wait and see' attitude as to how to act with Godou, and has at times provided aide to him. She seems to still be deciding whether or not he is an enemy of hers, or possibly something like an ally, a friend, or even more. Thus Athena develops feelings for Godou.
When she finally had her final battle against him, Athena won, but didn't slay Godou. Instead, she chose to grant him a gift from her divine wisdom. This is the first known case of a Heretic God granting a Campione power of their own free will and showing that she might be romantically interested in him.
Ever since the battle with Athena, Lancelot has been looking forward to fighting Godou in a passionate life and death duel. She doesn't have any problems with teaming up with him (even though she used her Authority on him). She has now become his Authority (Lance of White Knight).