Shun Kurosaki/Relationship

Ruri Kurosaki
The two are siblings, and seeing from Shun's determination to find her, they had a close relationship. He goes as far as to randomly target any Duelist from LDS in attempt to bargain Reiji Akaba for her. His feelings for his sister is so strong that he didn't hesitate to threaten his own best friend, Yūto, if he feels he's getting in his way. The thought of her capture easily makes him enraged and he will start Duelling mercilessly against anyone affiliated with Academia.

Yūto
Shun and Yūto are best friends, both have known each other for a long time. Although there have been disagreements and differences between their ideas, they have a lot of faith and trust in each other. Yūto acted as a voice of reason for Shun, stopping him whenever he did something reckless out of concern for his well-being. Shun also considered Yūto as his one and only best friend, showing concern when Yūto fought with Yūgo when a Synchro Summon was detected and wished to assist his friend if not stopped by Reiji. Shun becomes worried when he couldn't contact Yūto and angrily accused Yūya of harming and stealing Yūto's card. In his rematch against Dennis, Shun Duelled fiercely on his behalf. Though, despite their strong friendship, Shun doesn't hesitate to threaten Yūto if he feels Yūto getting in his way on saving his sister.

Kaito Tenjō
Kaito is Shun's Resistance comrade. Before the invasion, he and Kaito were rivals due to their different school branches and had friendly Duels several times. Shun respected Kaito as fellow Duelist and rival, and later values him as important comrade after both joined the Resistance. While Kaito also feels the same way, the resulting invasion causes Kaito to refuse trusting people from another dimension, even if it's Shun himself telling him that they are his trusted allies, which partly leading Kaito to distancing himself from him and the other Resistance members.

Reiji Akaba
Despite previously being opposing forces, they team up for their own gains. Shun had hoped to bargain Reiji for Ruri, but ended up joining LDS to find more opportunities to find Ruri. In turn, Reiji has informed Shun on what his father is up to. The two share a common goal, to find Reo Akaba and know what he is up to. Shun is shown to not fully trust Reiji and is frequently annoyed when his demands to take action are refused, forcing him to stay back and watch. Reiji often has to request his subordinates keep Shun under vigilance to ensure he doesn't do anything reckless that can affect his plans to recruit Lancers. In spite of his annoyance, Shun usually relents and follows Reiji's instructions.

Lancers
Shun initially didn't see any member of the Lancers as comrades and only works with them as a mean to reach Academia and rescue his sister. This was worsened when Dennis' true identity was revealed, leading him to distrust them. When they were separated during their arrival in the Synchro Dimension, he assumed that they had become lost between dimensions and did not even bother to search for them. His perception changes after forming a friendship with Crow in their Duel, where he began to consider them his comrades. The Lancers finally earned Shun's complete trust after Yūya's Duel against Jack in the final match, as the Duel and its result made Shun understands that the Lancers, particularly Yūya, also wishes to stop Academia and end the war as much as he does. Since then, Shun truly values the Lancers as his allies, which is shown when he asked Kaito to trust Yūya and the others like he does.

Crow Hogan
Crow has strong influence to Shun's growth. Shun initially saw Crow as nothing more than another enemy while Crow saw Shun as an outsider who dragged his own war into City due to the misunderstanding about Yūya. However, after Shun saw how the children cheered Crow and the latter's great concern for them made him remembered of the children who used to cheer him on back at Heartland. Also, Crow's struggles as a Commons made him to realize that they had a great deal in common, particularly having people that they swore to protect. His demeanor towards Crow changed from that point on, and he genuinely enjoyed the rest of the Duel and wholeheartedly accepted his defeat at Crow's hand. Crow's view towards Shun also changed after Shun rescued Tanner. This led them to develop respect for one another, and b efore parting ways, both Shun and Crow accepted each other as comrades. Shun's growing friendship with Crow also made Shun to open up more to the Lancers and eventually accepted them as his comrades as well.

Sora Shiun'in
Sora is shown to be very hostile to Shun. When they Dueled for the first time Shun vowed to not to show mercy on the fusion user (not knowing at the time he is a fusion user ) Sora initially treated Shun kindly in their dueled and when he saw Sora entertaining him the he began to talk about the days in Heartland. Realizing that Shun is from Heartland, Sora decide to show his true colors and taunted him really badly, enraging Shun who in return defeated and gravely injured Sora. Sora refused to accept his loss against Shun and develop a deep grudge and hatred for him and when he return to standard Sora successfully got his revenge and defeat Shun brutally. While their relationship after Sora betrayed Academia is unknown, Shun doesn't seem to be wary nor objecting the fact that Sora was helping them when they confront Roget.

Dennis Macfield
Shun's relationship with Dennis is less than great even before Shun found out his real alliances. Before their first Duel, Shun saw Dennis' Xyz Summoning as nothing but a fake, something that offended the latter who in return insulted his monsters, sparking a rivalry between them. Shun's hostility towards Dennis increased when he became suspicious about him as he showed tactics comparable to that of veteran war Duelist. When Shun finally found out that Dennis was from Academia, furthered by the fact of his role in Ruri's capture, his rage reached a zenith to the point Shun almost resorted to violence when he was unable to turn him into card. This revelation consequently also led Shun to momentarily distrustful of Lancers.