Whether they're actually guarding the galaxy or trying to get all they can out of it, this squad tends to make enemies easily. Their first real mission brings them into the crosshairs of the Universe Church of Truth, which leads to the return of Adam Magus, an evil version of Adam Warlock.
Thanos shows up on their radar, and not just because Drax was designed to kill him or Gamora has been wanting to do the same thing for most of her life. The rest of the team firmly opposes his views on killing every living thing in the universe.
The Guardians also run afoul of Emperor J’Son of Spartax, otherwise known as Peter Quill’s biological father. After being dethroned because of his son’s actions, J’Son turned himself into Mister Knife and threatened all of existence by trying to steal the Black Vortex.
Before launching the Guardians of the Galaxy, Peter Quill became a brother-in-arms to Nova during the Annihilation Wave. That relationship carried over to both the Guardians and the Nova Corps.
On Knowhere, the team works closely with Cosmo. They also have dealings with Ronan the Accuser, the Kree, and other races, including the Inhumans. After the team visits Earth for the first time as a group, they work well with the Avengers and were even welcomed by other Earth heroes like Iron Man, Captain Marvel, Venom, Kitty Pryde, and the Thing into their ranks.
Guardians Go on Tour
The group had its roots during the second Annihilation conflict when Ultron used the Phalanx to infect the Space Knights, sending the already-weakened Kree Empire into a downward spiral.
Peter Quill, otherwise known as Star-Lord, had worked to put a stop to the initial Annihilation Wave, but inadvertently allowed Ultron's virus to take control of Hala. The Kree then tasked him with a veritable suicide mission backed by Mantis, Captain Universe, Bug, Deathcry, Rocket Raccoon, and Groot. Though they ultimately succeeded in their mission, not everyone survived.