Shingo Sawatari/Relationship

Reiji Akaba
Shingo is shown to greatly admire Reiji's dueling abilities as shown when he bragged about how he was well known for his multiple summoning methods to Dennis. Reiji in return, is shown to have some faith in Shingo's abilities as shown by how he entrusted Shingo with the task of taking Yūya's Pendulum Summons, had him test a Yosenju Pendulum deck, and had him become a Lancer to aide the others during the invasion by the Obelisk Force. Reiji also taught Shingo how to Pendulum summon.

Yūya Sakaki
At first, due to his task of stealing Yūya's pendulum monsters as well as kidnap his friends to force him to duel in order to test them, Yūya immediately disliked Shingo. Shingo's defeat at Yūya's hands and losing the Pendulum cards caused Shingo to form a bitter rivalry with him. However, things changed during their second duel in which they both seemed to care about each other. After generously offering to duel Yūya anytime the latter wanted, they appeared to have buried the past and became friends. Although their behaviors still seem to annoy each other, they still appear to be concern for each other in important scenarios such as when Yūya lost Yuzu and Shingo was defeated and captured by Security. Their common love for entertaining the crowed also helped improve their friendship which also allowed them to work well together in action duels. While he was dueling Yūgo, Yūya who was linked to Yūgo and fighting beside him, was worried about defeating Shingo and sending him underground. This proves Yūya cares about Shingo as a friend.

Crow Hogan
When Crow and his gang saved Shingo and the other lancers form security, Shingo showed politeness and gratitude to Crow. While Crow found Shingo's rants about the Lancers and Standard Dimension strange, he didn't seem to dislike Shingo. After Shingo defended Crow from a large Security guard which allowed Crow and his friends to escape, they seemed to have gained a lot of respect for each other as shown by giving each other a thumbs up sign of respect.

Yūgo
During their duel, Shingo and Yūgo showed respect to each other and complimented their skills. When Yūgo was pushed into a corner by Shingo's tactics, he remarked Shingo was a good duelist. After their duel, Shingo and Yūgo left on friendly terms as shown by how Yūgo was quite surprised to see Shingo get taken away by security.