Squadron Supreme is a group of alien superheroes from a distant world similar to the Avengers. They chose solve their planet's problems by taking control of the planet, consisted of Hyperion, Princess Power, Nighthawk, Speed Demon, Doctor Spectrum, and Nuke. Being partially responsible for the chaos enveloping their world, they chose to take control of the planet to solve its problems. As such they took active responsibility for more than just fighting crime and supervillains and took on poverty and hunger, the environment, and public health.
They are shown in a flashback in the episode "Hyperion", where the Squadron Supreme is presented as heroes from Hyperion's home world who were killed when the planet was destroyed in a civil war. This was proven false in the episode "Nighthawk", when Nighthawk appears on Earth and uses S.H.I.E.L.D.'s contingency plan on the Avengers. When Falcon is his captive, Nighthawk mentioned that he is the "architect" of the Squadron Supreme while Hyperion was the "hammer" of the group. It was also mentioned that the rest of the Squadron Supreme are heading to Earth. At the end of the episode, Hyperion springs Nighthawk from his cell on the Tri-Carrier. They both leave to get their team back together. In the episode "Dark Avengers," Nighthawk and Hyperion have reunited with Zarda, Doctor Spectrum, and Speed Demon. Using the Reality Stone, Dr. Spectrum alters reality so the Avengers are all criminals with darker costumes and the Avengers Tower is headquarters of the Squadron. Due to a spike in energy, Iron Man sees the real reality and manages to convince his team to come together. However, Spectrum has created a machine that will give him complete control over reality, and plans to alter history so the Avengers were never born. Captain is able to get ahold of the stone and revert reality to normal. The Squadron leaves with Nighthawk activating charges placed at the base of Avengers tower. The Avengers manage to prevent the structure from falling onto New York in time for J.A.R.V.I.S. to activate the repair systems. Power Princess reappears in the episode "Secret Avengers," where she attacks Crimson Dynamo of the Winter Guard and tries to take a key from him. The Squadron planned on using the key to activate a power source that was taken by the Winter Guard from S.H.I.E.L.D., who first confiscated the source from HYDRA. After Power Princess sent Crimson Dynamo flying into a fast-moving river, Captain America's team of S.H.I.E.L.D. Avengers attacked Power Princess. During the battle, Power Princess threw her sledge and severely damaged a nearby bridge, forcing the Avengers to save the civilians while she escaped. The Squadron returns in the episode "Terminal Velocity." When Hulk and Thor retrieve a communications satellite for Iron Man, the Avengers discover a bomb made by Nighthawk. Iron Man tries to fly the bomb away, but is attacked by Hyperion. Hulk manages to catch the bomb and bear-hug Hyperion in midair, causing the bomb to explode between them without collateral damage. During the ensuing battle, Hyperion is captured in a stasis field, but Speed Demon sneaks into the tower. Unseen, Speed Demon kicks Hulk through a wall and breaks Hyperion out of his cell. Hyperion then flies off, leading most of the Avengers to the ocean where he traps the Aven-Jet in his vortex breath. Meanwhile, Speed Demon uses his enhanced powers to trap the Hulk in the episode "Speed Time," where everyone in it moves too fast to be seen. Hulk manages to warn Iron Man, and Iron Man discovers that Speed Demon has accelerated Hulk's gamma energy, turning him into a gamma bomb. Hulk leads Speed Demon into the stasis field, which Iron Man activates, causing them to slow down. Hulk destroys the belt that enhanced Speed Demon's powers and channels the extra energy into super speed to chase Speed Demon to Hyperion, where Hulk tackles them and takes them to a nearby deserted island, where Hulk releases his energy, knocking Hyperion unconscious. Speed Demon brings the unconscious Hyperion to Nighthawk's hidden base, where Speed Demon gives Nighthawk a flash drive containing copies of all of the Avengers' files. Nighthawk smiles and reveals that his plan is only beginning. In the episode "Spectrums," it was revealed in footage found by Falcon that Nighthawk and Hyperion attached the Power Prism to Doctor Spectrum which caused him to destroy the Squadron Supreme's planet. After Ant-Man separated the Power Prism from Doctor Spectrum reverting him to Billy Roberts, the Power Prism made its way back to Nighthawk. Upon the Power Prism no longer needing a host, the Power Prism forms a new body that resembles Doctor Spectrum as Nighthawk welcomes it into the Squadron Supreme. In the episode "Midgard Crisis," Power Princess plotted to sway an Avenger to her side when she used her training island to try to convince Thor. After this plot failed, Zarda told Nighthawk the outcome for the mission and that she was wrong about her original outcome. In the episode "Avengers Last Stand," the Squadron Supreme make their move with the capture of Captain America and Iron Man. While each of the Avengers and Squadron Supreme members transported to different locations like the arctic and an abandoned factory, Falcon was left to fight Nighthawk. Once both groups have been transported back from their locations by Falcon. Then the Squadron Supreme use Stark Tower to try to transport Manhattan to Limbo. With Ant-Man's help, Falcon prevents this from happening only for the Squadron Supreme's citadel to rise and fire beams into the Earth. While Thor fights the Squadron Supreme, the other Avengers free Captain America and Iron Man only to discover that the citadel is restoring Nuke who then destroys the citadel. With Thor defeated upon Nuke reunited with the Squadron Supreme, Nighthawk announces his demands on television and showing a defeated Thor as proof that the Avengers are defeated. The Avengers are shown to have survived the explosion and plan to reclaim Earth from the Squadron Supreme. In the episode "Avengers Underground," the Squadron Supreme now rules the Earth, having dealt with Attuma's forces while leaving one alive to tell Attuma what he just saw, shackled Red Hulk, trapped Doctor Strange in a special container, and kept Spider-Man occupied with one of their Squadron Bots. However it is clearly evident that there is much infighting amongst the ranks. So after dividing the Earth up, the Avengers then take them down. Iron Man frees Thor and disables the Squadron Supreme's communications. Then Hawkeye and Hulk deal with Speed Demon as Falcon, Thor, and Iron Man trap Zarda and Nuke in the same box. Then Ant-Man transfers the Power Prism's powers to Captain America where he turns the sun blue so Black Widow can defeat Hyperion. As part of a contingency plan, Nighthawk then teleports Nuke and Hyperion to the tower where Hyperion absorbs Nuke's powers with the intent on destroying Earth. As Nighthawk prepares to leave Earth, Iron Man defeats him and the rest of the team stops Hyperion from reaching the planet's core. The Squadron Supreme is later mentioned to have been placed into a special wing of the Vault.
- The Squadron members are an obvious homage to the DC superhero team, The Justice League.
- Nighthawk - Batman
- Hyperion - Superman
- Power Princess - Wonder Woman
- Speed Demon - The Flash
- Doctor Spectrum - Green Lantern (John Stewart)
- Nuke - Firestorm