|First appearance||"Guardians of the Galaxy #1"|
On his home planet, Groot was considered mentally challenged, only able to say the words 'I am Groot' when most of the species could talk like normal humans. When the two heroes Star-Lord and Quasar showed up, he saved them from a monster and he joined the Guardians.
They soon recruited the talking raccoon, Rocket, who Groot formed a friendship with. When the Guardians fought the mighty Thanos they got his servant, Adam Warlock to join the Guardians. He used his soul gem to allow Groot to speak normally.
Later, the Guardians were teleported into a whole other star system, where they met the alien who had formerly encountered the Avenger, Thor. They teamed up with Beta Ray Bill and he joined the Guardians.
When one of the Guardians's enemies, Korvac, came to Earth he was taken in by the Avengers. But the Guardians tried to stop him. The Avengers thought they were bad guys so they fought, but they eventually made amends and stopped Korvac.
During one mission, the Guardians went to the Skrull home world, Skrullos, to save it from being devoured by Galactus. They were unsuccessful. He ate the planet, but the Skrulls escaped. The Guardians barely managed to survive themselves.