Atsuhiro Sako/Relationships

Tomura Shigaraki
Mr. Compress appears to have a sense of loyalty to Tomura Shigaraki similar to Kurogiri. His actions and instructions during the battle between All Might and All For One were thought out for Tomura's interest.

After his teammates escaped, Mr. Compress was seen alongside with Tomura while the other members were separated elsewhere.

League of Villains
Mr. Compress seems to genuinely care for his teammates. He does not view his teammates as merely hoodlums who commit acts out of just evil purposes. Rather, he seems to understand their circumstances and can relate to their situations.

During the battle between All Might and All For One, he took charge of the situation for the best interests of his teammates: instructing appropriate actions for Tomura and compressing Dabi in order to carry him to safety.

After the battle, he made sure that the members regularly contacted one another to make sure none of them are caught and puts them in danger.

Overhaul
Mr. Compress hates Overhaul after he destroyed his left arm while trying to stop him. His hatred was so big that even his clone created by Twice after this incident wanted revenge for the loss of his arm.

His revenge would come after the fall of the Shie Hassaikai and the capture of Overhaul. The League of Villains assaults the police van that transported Overhaul to prison. Then, Tomura and Mr. Compress confront Overhaul and tell him how much they hate him. Mr. Compress agrees with the statement and compresses part of Overhaul's left arm, severing it at the wrist as an act of retribution.