<Li> Chris Pratt as Peter Quill / Star - Lord: The half - human, half - alien leader of the Guardians who was abducted from Missouri as a child in 1988 and raised by a group of alien thieves and smugglers called the Ravagers . About the character, Pratt said, "He had a hard time as a kid, and now he goes around space, making out with hot alien girls and just being a rogue and a bit of a jerk, and through teaming up with these guys, finds a higher purpose for himself ." He also added that the character is a mix of Han Solo and Marty McFly . Pratt, who was mostly known for playing supporting characters, including Andy Dwyer on the television series Parks and Recreation, initially turned down the role . Pratt had lost weight to portray fit characters in films such as Moneyball and Zero Dark Thirty, and had given up ambitions to play the lead role in action films after humbling auditions for Star Trek and Avatar . Casting director Sarah Finn suggested Pratt to Gunn, who dismissed the idea despite struggling to cast that role . Despite this, Finn arranged for a meeting between the two, at which point Gunn was immediately convinced that Pratt was perfect for the role . Pratt also won over Feige, despite having gained weight again for Delivery Man . Prior to filming, Pratt underwent a strict diet and training regimen to lose 60 lb (27 kg) in six months . Pratt signed a multi-film contract with Marvel, and was granted a temporary leave from his work on Parks and Recreation in order to accommodate his participation in the film . Wyatt Oleff portrays a young Quill . </Li> <Li> Zoe Saldana as Gamora: An orphan from an alien world who seeks redemption for her past crimes . She was trained by Thanos to be his personal assassin . Saldana said that she became Gamora through make - up rather than computer generated imagery (CGI) or performance capture . On taking the role, Saldana said, "I was just excited to be asked to join by James Gunn and to also play someone green . I've been blue before (in Avatar)." Saldana described Gamora as "...a warrior, she's an assassin and she's very lethal but what saves her is the same thing that can doom her . She has a sense of righteousness . She's a very righteous individual ." </Li> <Li> Dave Bautista as Drax the Destroyer: A warrior who seeks to avenge his family's death at the hands of Ronan . On relating to the character, Bautista said, "I can just relate to Drax so much it's not even funny . Just the simple things that we have in common . Simple things like the tattoos, the tragedy--because you know, I had a bit of tragedy in my life as well . So it's really easy for me to pull from that ." Bautista also said that there was "a lot of comic relief to Drax", but the character was not aware of it . Bautista stated that he did not do much preparation for the role, because "Luckily, for me, I'm a lifelong athlete and I adapted real quick ." Bautista's makeup took approximately four hours to apply, though it could be removed in just 90 minutes . Drax has various scarring patterns on his body, which replace the simple tattoos from the comics, each having a specific story . Additionally, his skin tone was changed from the bright green in the comics to a muddier grey, to avoid visual similarities to the Hulk . </Li> <Li> Vin Diesel as Groot: A tree - like humanoid who is the accomplice of Rocket . Diesel stated that he provided the voice and motion capture for Groot, after originally being in talks to star in a new Phase Three Marvel film . Diesel also provided Groot's voice for several foreign - language releases of the film . Krystian Godlewski portrayed the character on set, though his acting was not used in the final character CGI . On the character, which Gunn based on his dog, Gunn said, "All the Guardians start out the movie as bastards--except Groot . He's an innocent . He's a hundred percent deadly and a hundred percent sweet . He's caught up in Rocket's life, really ." Gunn added that the design and movement of Groot took "the better part of a year" to create . Gunn added, "The ways in which Vin Diesel says,' I am Groot,' I am astounded . All of the' I am Groots' that were earlier voices didn't sound very good at all...Vin came in and in one day, laid down all these' I am Groot' tracks, and he's a perfectionist . He made me explain to him with ever (sic)' I am Groot,' exactly what he was saying...It was amazing when we first put that voice in there how much the character changed and how much he influenced the character ." Regarding the limited words used by Groot, Diesel said in many ways this was, "...the most challenging thing to ask an actor to do ." Diesel found an emotional note in his performance, invoking the death of his friend and Fast and Furious co-star Paul Walker, saying, "This was in December (2013), and the first time I came back to dealing with human beings after dealing with death, so playing a character who celebrates life in the way Groot does was very nice ." Groot's form and size - changing abilities are seen, with Gunn stating that he has the ability to grow in the film . </Li>

Who plays the big guy on guardians of the galaxy