Gyoro Gyoro is something like Orochi's master, and their relationship is cold and professional. Gyoro Gyoro is responsible for stimulating Orochi's transformation from a human to the Monster King he is now, and in the process has trained him to obey his every command. Whether Orochi was willingly brainwashed or not is uncertain. He lets Gyoro Gyoro do the talking when it comes to leading the Monster Association, and pays great heed to any advice or orders he gives him, such as when Gyoro Gyoro recommended he spare Do-S because of her useful powers. He does appear to still have his own say, shown when he decides to eat Awakened Cockroach on his own and gives Garou a unique challenge to prove his loyalty. He has even been able to come out from under Gyoro Gyoro's influence as well, as shown when he ignored him to go fight Saitama instead.
Psykos is the one who recruited Orochi as a human to become a monster. Their goals somehow aligned, and he voluntarily underwent her brutal experimentation. Although Psykos claims no monster knew of her connection to Gyoro Gyoro, it can be safely assumed that Orochi was aware of it due to their close partnership and long history. However, it's revealed that Orochi has been hiding his true power from Psykos, and while reforming himself after Saitama's punch, Orochi had no qualms with absorbing Psykos into his biomass, and even taunted her while doing so.
Orochi is the one who initially bested Gouketsu and gave him a Monster Cell, recruiting him into the Monster Association. He is shown to have gained a fondness for him, promoting him to an executive in the organization and sometimes asking Gyoro Gyoro about his whereabouts when he was deployed. He seemed troubled when he heard that Gouketsu had been killed.
Overgrown Rover is one of the few beings who Orochi actually trusts and respects to some extent. He was well aware of Rover's strength, and was shocked when he disobeyed his commands and ran away from Saitama when he ordered the canine beast to attack.
Other Mysterious BeingsEdit
Orochi was the figurehead of the Monster Association, a powerful banner under which Gyoro Gyoro could unite Mysterious Beings. Most members of the Monster Association respected him out of fear, and did their best to stay on his good side. Some members, however, did not care about Orochi and were clearly only in the Monster Association for their own goals. An example of this is Black Sperm, who was very vocal about his lack of interest in the Orochi-ruled world of the future. Orochi, on the other hand, didn't seem to care for his underlings at all and devoured and massacred them with little thought. If a Mysterious Being was in his way or failed to produce results, he had no problem with disposing of them. However, he did respect those that were powerful or useful enough, such as the aforementioned Overgrown Rover and Gouketsu.
Orochi didn't immediately voice any opinion of Garou, and simply gave him a challenge in order to ensure his loyalty before giving him any responsibilities. However, when Garou returned to dismantle the Monster Association instead, Gyoro Gyoro ordered him to punish the rebellious recruit. Orochi showed little mercy with Garou, and swiftly defeated him with little trouble. He seemed amused at Garou's uncanny confidence in such dire odds, and mocked him for thinking he could make him feel fear. Whether he was aware of Gyoro Gyoro's plan to eventually replace him with Garou or not is unknown.
Somehow, Orochi was able to notice Saitama from afar (possibly because of the shockwave of his punch on Overgrown Rover) and immediately became interested, overriding Gyoro Gyoro's brainwashing and heading straight to him. Upon meeting him, Orochi could immediately tell that Saitama was not as weak as he appeared. Once he put together that Saitama was responsible for the deaths of two of the Monster Association's strongest executives, Gouketsu and Elder Centipede, he became excited at the thought of such a strong opponent and entered his most powerful form to fight. Like Boros, Orochi's slipping sense of self and interest in life were rejuvenated upon his encounter with Saitama, and helped him to regain some of his consciousness from the numbing effects of Gyoro Gyoro's influence. He even went to such lengths as to introduce himself to Saitama, speaking more than ever before. Unfortunately, Saitama was much less interested than he was, and his overpowering strength quickly ended the confrontation. Orochi admitted that he had finally felt fear again during their battle. After his recovery and fusion with Psykos, Orochi claimed that he would go get revenge on Saitama after they defeated Tatsumaki.