<Li> Lee Pace as Ronan the Accuser: A Kree radical who agrees to retrieve an artifact for Thanos in exchange for eradicating his mortal enemies, the Xandarians . Ronan and his Sakaaran army hunt down the Guardians when they interfere with his goals . Describing Ronan, Gunn said, "He is the primary villain, and he is a really twisted guy, he has a really religious bent in this film . He has a very sick and twisted view of what morality is; strength is virtue and weakness is sin and that is what he lives by, and I think he is very scary because of his beliefs, which are real to him ." Pace, who originally auditioned for Peter Quill, described Ronan as a "psycho" and a "monster". </Li> <Li> Michael Rooker as Yondu Udonta: A blue - skinned bandit who is the leader of the Ravagers and a paternal figure to Quill . Yondu helps Quill to steal the orb before Quill betrays him, leaving Yondu and the Ravagers to chase the Guardians . On the character, Rooker said, he has "some interesting issues--not a good guy, not a bad guy . There's hope and there's a heart inside Yondu ." Gunn created the film's version of the character specifically with Rooker in mind, while borrowing the character's mohawk and use of a whistle - controlled arrow from the comics . Rooker fully committed to the role once he knew his role on the TV series The Walking Dead would be ending . Rooker's makeup took approximately four hours to apply . </Li> <Li> Karen Gillan as Nebula: An adopted daughter of Thanos who was raised with Gamora as siblings and is a loyal lieutenant in the employ of Ronan and Thanos . About the character, Gillan said, "She is the female villain of the film...She is very sadistic and evil, but I like to think for a very valid reason ." She also added, "I think she's a really interesting character . What I like to play around with is how jealous she is . She's Gamora's sister, and there's a lot of sibling rivalry . That's the most interesting aspect to me, because jealousy can consume you and turn you bitter, and ugly . And she's a total sadist, so that's fun too ." Gillan researched the ancient Spartans, shaved off her hair, and trained for two months for the role . The character's makeup took approximately four and a half hours to be applied . </Li> <Li> Djimon Hounsou as Korath: A Kree ally of Ronan who is a feared intergalactic hunter . As to why he took the role Hounsou said, "I have a four - year old son who loves superheroes from Spider - Man to Iron Man to Batman . He's got all the costumes . One day he looks at me and says' Dad, I want to be light - skinned so I could be Spider - Man . Spider - Man has light skin .' That was sort of a shock . This is why I am excited to be a part of the Marvel Universe, so I could hopefully provide that diversity in the role of the superhero ." </Li>

Guardians of the galaxy cast gamora's sister