Skyquake (Twin Brother)
Skyquake and Dreadwing's were twin brothers due to the result of a split-spark. Dreadwing came to Earth in order to reunite with Skyquake, however when Dreadwing sensed and actually heard of his brother's demise by Megatron and shown by Soundwave, he vowed to avenge Skquake by destroying every single Autobot on Earth. When Dreadwing had learned that Starscream resurrected his brother using Dark Energon, Dreadwing was shocked as he yelled at the sky. As a result, Dreadwing became disillusioned with the Decepticons. His brother's death was the reason for Dreadwing aiding the Autobots by giving them the Forge of Solus Prime and attempted to kill Starscream. This proved that Dreadwing's loyalty to his late brother was stronger than his faith in the Decepticon cause as well as his loyalty to Megatron. This also shows that Dreadwing had a strong connection with his brother, even when they never interacted on screen.
Dreadwing and Breakdown seemed to get along well. When Dreadwing was tasked to kill Starscream he brought Breakdown along. Breakdown had no complaints during their assigned task as they both tried to cover up around Airachnid. However, Airachnid knew as she goaded Breakdown into losing his temper to attack her, despite Dreadwing's efforts in calming Breakdown. When Airachnid turned the tables and killed Breakdown, Dreadwing was silent when he went back to the warship where Megatron was trying to explain that their inability to locate Breakdown's signal was unclear and was angry at Dreadwing for not recovering any remains of Breakdown.
Airachnid seemed to get along with Dreadwing until Dreadwing was tasked by Megatron to terminate her with Breakdown as his backup. Airachnid considered herself and Dreadwing to be Megatron's proficient warriors, which enraged Breakdown when she revealed that she was referring to herself and Dreadwing rather than Breakdown. This soon led to an angry Breakdown to chase Airachnid, that resulted in his own demise and Dreadwing being webbed to a tree by Airachnid.
Knock Out and Dreadwing are usually seen to hang out. In Patch, Dreadwing came to "assist" Knock Out, which he prevented Knock Out from separating Megatron from his mind and body through the cortical physic patch. After they both witnessed an flashback that Starscream had revived Skyquake as an undead Terrorcon zombie, Dreadwing remained paused and Knock Out called it "awkward". Knock Out seemed concerned when Dreadwing vanished from the room.
Dreadwing was a high ranking Decepticon Seeker who was very loyal to Megatron. He was made Megatron's second in command when he disobeyed Megatron's orders in following him to a cave where Megatron fought Airachnid's insecticon. In Dreadwing's last moments where he chose avenging his brother by trying to kill Starscream, Megatron was forced to kill Dreadwing. Though Megatron was killed by Bumblebee, he avenged everyone who was killed by Megatron including Dreadwing.
At first, it seemed like Dreadwing saw Starscream as a traitor and deserter. Dreadwing opted to take Starscream back to Megatron as his prisoner during Dreadwing's hunt for the Apex Armor. When Starscream acquired the Apex Armor, he took on Dreadwing and mocked him by stating he will reunite him with his fallen twin. When Dreadwing learned from the Cortical Psychic Patch that Starscream desecrated his brother, Dreadwing vowed revenge and was close to killing Starscream.
Optimus Prime (formerly)
Dreadwing wasn't very fond of Optimus, learning that it was him and an Autobot scout who killed his brother, he swore vengeance upon them. It would also seem that Dreadwing and Optimus worked well in their alliance in taking down Starscream who was in the Apex Armor. After learning from the Cortical Psychic Patch that Starscream dishonored his brother Skyquake's death by turning him into a Terrorcon, he had given the Autobots the Forge of Solus Prime in hopes it would avenge him. He seems to respect Optimus greatly as an adversary and Optimus, likewise, felt the same way. Optimus even offered Dreadwing chances to join the Autobots.
Dreadwing captured Bulkhead in Loose Cannons. Dreadwing used Bulkhead as bait to lure Wheeljack and Optimus Prime. Bulkhead was strapped to a crate on a docks where Dreadwing also strapped one of his bombs on Bulkhead. Eventually, Dreadwing had to disarm the bomb on Bulkhead when Optimus trapped Dreadwing with a claw machine on the docks. In Hard Knocks, Bulkhead faced against Dreadwing again and mentioned how Dreadwing doesn't have the "ball bearings" to fight in person. Dreadwing accepted Bulkhead's offer to fight and they fought for a short time. However, when Dreadwing was ready to arm his bomb that he placed on Bulkhead during their fight, Bulkhead had placed the bomb on Dreadwing's back. Dreadwing took it off and threw it into the air. In Regeneration, Bulkhead went with Optimus, Arcee, Smokescreen and Bumblebee to see Dreadwing. Dreadwing gave them the Forge of Solus Prime but Bulkhead thought it could be rigged to blow up. Dreadwing told them about the Omega Keys and how he doesn't want to be in the Decepticons anymore. Optimus tried to recruit Dreadwing, but Dreadwing didn't take his offer. Bulkhead may have forgiven Dreadwing as he flew off.
Wheeljack faced against Dreadwing in Loose Cannons. Wheeljack told the Autobots that he fought Dreadwing in an outer space and that Dreadwing killed Seaspray with one of his bombs. Later, Wheeljack faced against Dreadwing again in a little canyon where Bulkhead waited to ambush Dreadwing. This turned out to be a trap where Dreadwing had placed a bomb below Bulkhead's hiding place above the canyon. The bomb exploded and left Wheeljack in a pile of rocks while Dreadwing captured Bulkhead. Optimus Prime helped Wheeljack out of the rocks and they went to find Bulkhead. Eventually they found Bulkhead who was strapped to a crate on a docks with Dreadwing's bomb placed on his chest. In the end, Dreadwing was trapped by Optimus and was forced to disarm the bomb. Before escaping, Dreadwing detonated the other bombs he had placed on the docks and they exploded some crates. Despite not knowing that Dreadwing gave the Forge to the Autobots, Wheeljack may have forgiven Dreadwing.