These are Knock Out's Relationships.
Breakdown was Knock Out's partner in the battlefield when he was alive. When on missions, they worked well together and were skilled enough to face Optimus on occasions. In fact one might call them buddies. Knock Out was greatly angered when he found out that Silas had dissected Breakdown and had taken over his body and was eager to dissect the one responsible when given the chance. Though he showed no knowledge that Airachnid was the one who killed Breakdown, nor did he seem to show too much remorse.
While very dismissive of the Decepticon Second-in-Command, often insulting him openly, Knock Out was eager to join Starscream in his attempted takeover of the Decepticons' and become the new Second-in-Command while Megatron was incapacitated (which didn't last long). In Regeneration, Knock Out helped place a T-cog into Starscream and told him the sugery was a success. Later, they argued over not wasting time and ended up using the Omega Keys to attack each other, which resulted in the answer to finding the Omega Lock. In Thirst, both Starscream and Knock Out created experimented with Dark Energon and Synthetic Energon into Silas, which resulted in negative results as Silas was able to infect Vehicons and nearly infected the entire ship. While hiding from the zombie infected vehicons, Starscream and Knock Out shared a moment that seemed to be their last. Starscream told Knock Out it was an honor to serve Megatron with him and in turn, Knock Out revealed he had admired Starscream's finish, despite him not being Breakdown. When Megatron confronted the pair, Starscream had blamed Knock Out for the incident, to which he looked on Starscream in betrayal. However, Knock Out turned against Starscream and joined the Autobots in Predacons Rising after Starscream rudely told him to "shut up" and he might have even thrown Knock Out out an airlock. Despite this, Knock Out was probably the closest thing Starscream has to a mean guy.
The human organization won Knock Out's ire when they captured Breakdown in Russia, and attempted to dissect him in their attempts to learn about Cybertronian biology. They unknowingly angered him further when they found his remains, left by Airachnid and used his corpse save their leader Silas. Knock Out took great pleasure in torturing MECH's leader Silas for some time, citing the Breakdown would have approved of the punishment.
Optimus Prime (formerly)
Knock Out complemented Optimus Prime on his tires in Deus Ex Machina and attacked Optimus with his energon prod. Knock Out fought Optimus in T.M.I. and lost in battle. Optimus is rarely seen to fight Knock Out on the show. In Predacons Rising, Knock Out joined the Autobots and reveals that he looked on to Optimus as a true role model when Optimus looks at his team before going inside the Core of Cybertron to restore life once more.
While the pair only met recently in Stronger, Faster, Ratchet proved himself more than a match for the Decepticons chief medic in both combat and in the scientific field. Despite this animosity, Knock Out seemed to appreciate when Ratchet thanked him for his assistance. Earning the Autobot doctor a sincere "you're welcome". When Knock Out joined the Autobots, he seemed to patch things up with Ratchet.
Knock Out was jealous of the Autobot's newest recruit the moment they met, not to mention the young Autobot had a flashier paint job and possessed the Phase Shifter (the very relic he'd found but failed to secure on a previous mission). He took malicious pleasure in torturing the new recruit. This animosity only grew when, after fighting Smokescreen trapped Knock Out in a wall before making his escape form the Nemesis. This eventually accumulated into Knock Out trapping Smokescreen in a wall as revenge after he and Starscream ambushed him. Despite this, Smokescreen and Knock Out are seen to reconcile after Knock Out joined the Autobots.
Knock Out was most frightened when he laid eyes upon Predaking's beast mode. He was extremely shocked when Predaking was able to transform into a robot form. Knock Out was not involved in Megatron's plan to let the Autobots terminate Predaking's Predacon brethren but he did grow suspicion if Predaking was to find out of their treachery. However, in Predacons Rising, Predaking and his two new Predacon brethren have teamed up with the Autobots, including Knock Out as new member, to fight Unicron's zombie army of Predacons. After the battle, Predaking and his brethren may have proven themselves to be valuable allies to the Autobots.
Bumblebee seems to have developed a rivalry with Decepticon Knock Out. Their rivalry was not noticeable when the two first met, but became abundantly clear between the time Bumblebee went with Jack to compete in races or when Bumblebee's T-Cog was stolen by MECH. In both instances, Bumblebee was taunted by Knock Out, either for not being as fast as him. Bumblebee fought Knock Out several occasions. During a relic hunt with Arcee in New York, Bumblebee fought Knock Out to get the Phase Shifter. During a hunt for the Omega Key, Knock Out used the resonance blaster against Bumblebee and Arcee. In Predacons Rising, Knock Out somewhat helped Bumblebee by providing information on the escape Decepticons. Later, Knock Out revealed that he wanted to join the Autobots and Bumblebee was disappointed that Knock Out destroyed the immobilizer. Bumblebee and Knock Out became allies after that.