Overhaul is the leader of his organization. He does not appear to have a level of respect or care for his subordinates beyond their use. This was evident when he used one of his subordinates as a human shield and chastises another subordinate for being slow.
Despite how he treats them, the members, particularly those of the Eight Bullets, value Overhaul as their leader and are willing to protect him. However, a few others respect his power but not necessarily his leadership and tactics.
Kai was taken in and raised by the Boss-man of the Yakuza. Kai views him as a father figure and believes he owes the old man a great debt for taking him in. Throughout his life, the Boss recognized that Kai was troubled and he would try to hone him into an honorable Yakuza. Kai would often lash out at anyone who badmouthed the Yakuza as a child. The Boss told a young Kai that Yakuza can't hurt innocent people but still thanked Kai for trying to protect their honor. This became a treasured memory for Kai as a reminder of his debt to the Boss.
But Boss's ideals and his own would often clash as Kai grew older. The Boss wanted Kai to stay away from villainy and drugs. He even refused Kai's plan to reinstate the Yakuza. Disappointed, Kai forced the old man into a coma. Even so, Kai still appreciates everything the old man did for him and only put him into a coma so he could repay his debt.
After becoming Overhaul, Kai takes care of the old man and even talks to him at his bedside. The Boss man is the only person Kai appears to care for and that he's ever showed empathy for.
Chronostasis is the aide to the Shie Hassaikai and one of the few members Overhaul does not treat like a disposable object. This is most likely largely because Chronostasis' abilities are of higher use than those of most of the members, making him a valuable asset to the organization, but it may also be because of the fact that he and Kai knew each other since childhood, which would mean the young leader holds him in higher regard than the newer members.
Mimic is a member of the Shie Hassaikai. Similar to Chronostasis, Mimic is treated as a valued member of Overhaul's organization and not considered expendable. Mimic is incredibly loyal to Overhaul. Despite being the Director of the organization, Mimic accompanies Overhaul during his exploits and protects him from potential threats.
Overhaul does not show interest in joining the League of Villains, due to their apparent lack of planning. He only sees their influence as a means for his motives. The League initially had an interest in Overhaul and his organization before coming into a disagreement when Overhaul brought up his motives. The meeting causes a skirmish, resulting in casualties on both sides. Himiko Toga and Twice become immensely upset at the death of Magne and Mr. Compress's lost arm. Despite this unstable relationship on both sides, Overhaul still encourages the League to figure things out before contacting him again.
Overhaul treats Tomura Shigaraki pragmatically, as he wants to bring out the full potential of the League by having them work under him. After his meeting with Tomura and agreeing to work as equals, he employs Himiko and Twice into his services as he sees their Quirks as powerful but also to have the two under his control. However, Twice and Himiko do not favor him and eventually sabotage his getaway plans during the Shie Hassaikai Raid.
When he is defeated by Izuku Midoriya and being transported to a hospital the League attacks the vehicle escorting him. Overhaul is not fazed by their appearance but he becomes angry when they steal his Quirk-Destroying Drug. His rage turns to fear as Mr. Compress and Tomura compress and decay off his arms as revenge for his actions against the League. Tomura taunts the helpless and powerless Overhaul for his "high and mighty" attitude and relying on his Quirk so much despite wanting to get rid of Quirks before leaving. Overhaul screams as they leave him, realizing everything he did had been taken away from him.
Due to being invaluable to his operations, Overhaul can't afford to kill Eri for rebellion, unlike his other subordinates. He allows her minimum luxuries, lucky to receive a single toy. To keep her under control, he mentally manipulates her instead. Using her father's accidental death against her, he constantly gaslights her. Overhaul claims her existence is "cursed" and his murders are her fault. Out of fear and misplaced guilt, Eri follows his orders so others don't get hurt. She's hyper-aware of his mannerisms, instantly knowing a tug at his glove, signalled he was threatening to kill someone. It's only when Mirio reveals Overhaul had manipulated her, does Eri have the confidence to escape him for good.
Overhaul locked Eri away from the outside world, forcing her back whenever she attempted to escape. Deprived of a normal childhood, she didn't know how to smile and lacked basic knowledge for her age. Regularly, Overhaul would perform tortuous surgery on her, even using his quirk to destroy and reassemble her body. He'd extract her blood to use as an ingredient in his drugs. When Eri is in public, he avoids suspicion with the persona of a strict yet regular father, getting irritated when bystanders pry. He calmly has excuses for her abnormal behaviour, blaming her as a "clumsy" and "badly behaved" child.
He's possessive over Eri, considering himself the only one to truly understand her quirk.When Heroes took Eri away from him, he had rare outbursts of rage. He ranted on how he owned her and how she was key in his vision for society. Resorting to extreme methods he'd usually find disgusting, he even fused with the bodies of deceased Yakuza, all to get her back. Once the Heroes succeeded in rescuing Eri and arresting Overhaul, he became depressed, his dreams falling apart with the loss of Eri's rewind.
Due to Overhaul placing her grandfather in a coma, Eri had no relatives that could adopt her. It forced the staff of UA High School to supervise her instead. While Overhaul was no longer physically in her's life, the trauma inflicted by him, still haunts her. It took Eri several weeks to simply smile for the first time. It would be a long process before Eri can start to live as a normal cheerful child.