Drax the Destroyer was actually human in the comics. His backstory is very similar in the movie, only his wife and daughter were murdered by Thanos in the comics as was he.
He was resurrected by the father of Thanos specifically to kill Thanos, which he eventually does.
Gamora is the adopted daughter of Thanos in both comics and film, however in the movies her backstory is slightly darker.
In both her parents are killed and she is rescued by Thanos, but in the movies it was Thanos who murdered her parents to begin with.
Gamora is far more sexualized in print, having more Tomb Raider level proportions. They dressed her up a bit more practically for the movies.
Far from being the anti-hero pirate Ravager from the film, Yondu’s print origins were of a hero. Yondu was the leader of the Guardians of the Galaxy and later even joined the Avengers.
Arrows are a part of his skillset in the comics as well, though he also occasionally will use a bow and not just, like, his mind.
Rocky, as he is introduced in the comics, is a space sheriff on an a planet that is an insane asylum (think Australia).
He was genetically modified by robot guards there who were bored giving him one of the most unique back stories in Marvel lore.
That may still be his origin in the movies, but if so it hasn’t been covered yet.
Probably the biggest difference between Groot on screen and off is his mastery of the English language. Though best known on film as only being able to say “I am Groot”, the tree like alien would speak often and eloquently though in more recent years has become accustomed to his pokemon like speech pattern like in the film.
He is also much larger, stepping in at about 25 feet tall.
He was introduced as a villain originally, set to conquer earth but was defeated by genetically engineered termites.
While totalitarian and evil in the movie, Ronan the Accuser is more of a warrier living by his code in the comics. Neither good nor bad he is closer has fought against and along side the Guardians of the Galaxy. He plays by his own rules basically.
Or at least he did.
Nebula in the comics has hair! Poor Karen Gillan, not sure if that was her choice to shave it or if they just told her it would make for a more authentic audition.
Petty quibbles aside, the biggest difference is probably that in comics she staunchly hated Ronan, far from being a loyal servant.
She did eventually get tons of cool cyborg parts, though she did start out with all of her original bits originally
Ayesha, the villain of Vol. 2 but originally appeared in Doctor Strange in the comics. A being that the good Doctor brought to life himself and she has gone by many names of her own choosing. She has had more names than P. Diddy.
Ego the living planet is more of Thor character than Guardians though he does appear from time to time. In Thor 228 he reveals that he was at one time a scientist who merged with a planet.
Mantis is a half Vietnamese and half German human in the comics, with later revisions adding more alien features. She is kidnapped by the Kree who believe she is a sort of celestial Madonna.
In the film she is an alien with emphatic abilities and assistant to Ego. Writer/Director James Gunn has said that her origin was changed because he wanted Star Lord to be earth’s only hero in the franchise.
Star-Lord/ Peter Quill is less of an outlaw and more of a cop in the comic books with a more uniform like appearance to his outfit. Though the defacto leader in the movies, he wasn’t introduced in the comics for seven years into the initial run.
In the comics Ego is not his father as he is in said in the trailer for Vol. 2 but the son of a alien emperor named J’son.
Via Insider
