Esdeath: Run was essentially Esdeath's second-in-command; she would often leave important and delicate tasks to him. He was highly loyal to her and followed her orders without question; however, Run initially thought that Esdeath, while powerful, was "scum" due to her sadistic nature and allegiance with the Prime Minister; he changed his mind after the General fell in love with Tatsumi, instead considering her to be "interesting".
Wave: While not much of it was seen, Run and Wave seemed to have formed a somewhat good friendship. Run comforted Wave after Bols' death, and they were seen hanging out together outside of work; Run also showed concern for Wave's health after the latter's fight with Syura, and later revealed his past to him and Kurome. Run's last words to Kurome were also about Wave, wishing for him to always remain his "kind self".
Kurome: Run, Kurome and Wave were seen hanging out together a few times, and Run was shown to care about Kurome's well-being, saving her life and protecting her during their battle against Wild Hunt members. When Run was about to die, Kurome turns him into her corpse puppet using her Teigu out of fear of losing another one of her comrades. Run, while he cared for her, was horrified by the fact that The Empire had caused such a young girl to become so mentally unstable.
Champ: The target of Run's vengeance. Run had been searching for Champ to seek revenge for his students who were raped and killed by Champ in the past. Later, as he managed to lure Champ into a trap, Run brutally tortured him with a smile on his face, revealing his twisted side. After being critically injured by Champ's attack, Run still found the strength to finish off the Wild Hunt member after the latter taunted him; however, as he was dying Run still admitted that torturing Champ was morally wrong as he referred to his approaching death as a "divine punishment" for such action.