Shuichi Iguchi/Relationships

Stain
Spinner has complete and total respect for the hero killer. It was Stain's words that inspired Spinner to become a villain and join the League of Villains. As a sign of his appreciation for the hero killer, Spinner made his villain costume very similar to that of Stain.

Following Stain's incarceration, Spinner has taken it upon himself to continue Stain's quest to rid the world of false heroes. He openly states that the League of Villains keep Stain's principles in mind when planning to kill someone.

Tomura Shigaraki
At first, Spinner joined the League of Villains thinking that it would help him to continue with Stain's legacy, so he had no problem with Tomura, following his orders without questioning them.

However, as the time progressed, Spinner began to have doubts about Shigaraki's actions. The first clue is when the League attack a police convoy to get at Overhaul, who was arrested. Spinner isn't happy about attacking police officers, who have nothing to do with creating a true society. Tomura Shigaraki reassures Shuichi that it is a necessary sacrifice.

Later, after the League had little benefit from other operations, Spinner finally loses his patience and begins to shout at Tomura that he has little faith in him and his ability to lead the League of Villains. He has openly questioned how Tomura and the League will help him bring Stain's goals to fruition.

Magne
Spinner and Magne teamed up during Vanguard Action Squad Invasion, despite their difference of opinions. Magne wanted to just kill without rhyme or reason, while Spinner thought it important to think about who to kill and who to spare in accordance with Stain's code of conduct. Their different mentalities and ideologies clashes when Magne tries to kill Izuku, being stopped by Spinner, since Stain saved Izuku's life, and therefore he considers him worthy to become a hero, a decision that Spinner wants to respect.

After they were subdue by Mandalay and Tiger, Magne blamed Spinner for their defeats.

Izuku Midoriya
Due to Stain not only sparing, but saving Izuku, Spinner has total respect for Izuku and his potential as a future hero. Spinner even went as far as to protect Izuku from being attacked by his fellow villain, Magne, just because he so deeply believes in Stain’s ideology.