These are Breakdown's relationships.
Breakdown first met Airachnid when they both stumbled upon one of the Iacon relic's, the polarity gauntlet. Airachnid took her attempt to bury him (non-fatally) very badly. Eventually, they both ended up teaming against Bulkhead and Arcee for the relic but lost. In Stronger, Faster, Breakdown talked about having a crush on Airachnid to a Vehicon soldier in the mine. Though the infatuation didn't last long as he was willing to help Dreadwing terminate Airachnid in Crossfire, but Breakdown was killed by her through the whole ordeal, even when Airachnid had no clue of his old feelings for her.
Possibly his most significant relationship is his partnership with Knock Out. Knock Out was Breakdown's partner on the battlefield when he was alive. When he was on missions, they would fight side by side and make trouble for the Autobots. When Breakdown was killed and his body was used by Silas, Knock Out wanted to seek revenge for his fallen partner, even as far to torture Silas inside Breakdowns's corpse.
Breakdown remained loyal to Megatron, often referring to him as master. Breakdown even attempted to avenge himself after losing an optic to M.E.C.H. by offering to retrieve the polarity gauntlet for Megatron. Megatron seemed to value Breakdown as soldier and was shocked to learn he was killed by Airachnid during an assassination attempt that Megatron sent Dreadwing, who brought Breakdown along to help terminate Airachnid but failed in the process.
Breakdown and Dreadwing seemed to get along well. Dreadwing had brought Breakdown along in an attempt, devised by Megatron, to offline Airachind. However, Airachnid knew it was a trap and got Breakdown to lose his temper, despite Dreadwing trying to calm him down. Breakdown was goaded into chasing Airachind while she had webbed Dreadwing to a tree and soon terminated Breakdown. Dreadwing was silent when he returned to the warship where he was scolded by Megatron for not recovering Breakdown's remains, since they were unable to locate Breakdown's signal.
Breakdown is one of the rare Decepticons who was an ally to Starscream. Starscream has commanded a rescue mission when Breakdown has captured by the MECH. After the rescue, Starscream said to Breakdown that he must choose between him and Megatron one day. But it never arrived because Starscream left the Decepticons temporarily and Breakdown was killed by Airachnid.
Bulkhead is Breakdown's nemesis when Breakdown was alive. The two of them had a history and faced each other on Cybertron and Earth. Breakdown seemed most surprised when Bulkhead rescued him from M.E.C.H.. Bulkhead didn't believe it either and he helped Breakdown get up. They formed a temporary alliance against M.E.C.H and destroyed most of them. Bulkhead came close to getting killed but Breakdown saved him from being blasted by M.E.C.H. When M.E.C.H left, Starscream showed up with several Vehicons. Starscream thanked Bulkhead for saving Breakdown but he asked Breakdown to destroy Bulkhead. Breakdown attacked Bulkhead and fell down when Bulkhead knocked him. The Decpeticons escaped when the Autobots arrived to back up Bulkhead, which caused Breakdown to leave as well. Later on, Breakdown teamed up with Airachnid against Bulkhead and Arcee to get the polarity gauntlet. Bulkhead and Arcee retrieved the weapon and returned to base with it. In The Human Factor, Bulkhead was shocked to see Breakdown again but this time it was Silas in Breakdown's dead body. After a battle and the aid from Smokescreen, Bulkhead and Smokescreen took down Silas. Bulkhed also seemed to let go of his old rivalry with Breakdown.
This human organization captured Breakdown before he could have finished off Bulkhead in Russia, where they attempted to open study Cybertronian biology on Breakdown. This did not sit well with Breakdown, and he was reluctantly freed by Bulkhead. He happily attacked as many of the M.E.C.H. Soldiers that he could find. In Crossfire, they unknowingly happened upon Breakdown's remains after Airachnid killed him when he attempted to assassinate her with Dreadwing. These humans later used his corpse to merge with Silas, which resulted in their own demise when Silas wanted to join the Decepticons and shot his own soldiers with the corpse's gun.