Gamora is a former assassin and a member of the Guardians of the Galaxy. She became the adopted daughter of Thanos after he killed her entire race. She served him for years before betraying him in an attempt to free herself from his ways. She was hired to steal the Orb, and became caught up in the Quest for the Orb, becoming friends with the other members of the Guardians of the Galaxy. After the Battle of Xandar, she left to work with them all. Having made a deal with the Sovereign to kill the Abilisk, Gamora was able to take back custody of her fugitive sister Nebula with the intention of finally bringing her to justice in Xandar.

The mission to punish Nebula was delayed however when Gamora and the Guardians came into contact with Ego, the long lost father of Star-Lord. While Ego claimed to just want to bond with his son, Gamora was suspicious and, alongside Nebula who had freed herself, discovered Ego's evil intentions to destroy and rebuild the universe. Upon this discovery, the Guardians teamed up to destroy the living planet, succeeding with the help from Mantis, who joined the group, but at the cost of Yondu Udonta sacrificing his life.