Rocket Raccoon

Background
Before becoming a Guardian of the Galaxy, Rocket was taken from his family and was enhanced by the scientists on the world, Halfworld. However, they never cared what happened to their experiments afterwards. However, the years of abuse and repetitive genetic rewrite caused him, calling himself Rocket, to develop a vain and chaotic personality, driving him into becoming a gun slinging mercenary. Rocket's Nova Corps criminal record includes 13 counts of theft, 23 counts of escape from his incarceration, 7 counts of mercenary activity, and 15 counts of arson.

Personality
Abused by many scientists for many years, Rocket grew a cold and distant person who never showed a sign of weakness. However, he was emotionally attached to his friends. He cares very deeply for his friends who have been identified as the only family he ever had. The only person he had was Nebula, who had comforted him over their losses.

By Guardians of the Galaxy Vol. 2, Rocket has also developed Quill's love of music, often playing it while also humming to the songs. This is further shown during their battle with the Abilisk, with Rocket rigging speakers to listen to tunes when they work.

Physical Appearance
Rocket is a Half-worlder resembling a Raccoon. He is an anthropmorphic animal due to being cybernetically enhanced. Rocket also has brown eyes and his quite short.

Abilities
Rockte is a talented pilot, an inventor, and has leadership skills.

Guardians of the Galaxy
Rocket makes his debut appearance in the 2014 film, Guardians of the Galaxy. He and Groot appear on Xandar, where Rocket spots Peter Quill, a young man who has a large bounty on him by his foster father, Yondu Udonta. Rocket and Groot attempt to kidnap Quill until they are fought by Gamora and arrested by the Nova Corps. The crew is sentenced to the Kyln, a high security prison. During their time there, Rocket threatened most of prisoners at the Kyln that none of them lay their hands on Peter Quill lest they go through them. Rocket also attempted to stop Quill from entering a conflict involving Gamora, who was threatened to being killed by Drax the Destroyer. After saving her, Gamora agreed to split the profits between her, Rocket, Groot and Quill in selling the orb to the Collector. The group are able to escape through Rocket's improvised plans. Rocket also makes a bomb out of parts from the Milano as they go to reach Knowhere.

Finally arriving on the planet, Rocket was with Groot and Drax when they were betting on Orloni. However, the trio entered a major, physical fight. However, Quill calmed Rocket down with the thought of four billion units. Without Drax, Rocket went with Groot, Gamora and Quill while visiting the Collector, where they learn that the content in the orb is the purple Infinity Stone, Power. The Collector's slave, Carina tries to take the stone for herself; however, she is killed and causes an explosion. Groot takes Rocket and runs with him as Quill and Gamora went for cover. Rocket attempted to dissuade Quill and Gamora from giving the Power Stone to Nova Corps. At that time, Ronan the Accuser arrives, as does Quill's adoptive father, Yondu, who attempts to chase after him. However, Rocket joins Gamora and Quill by stealing the miners' mining pods. The trio fight the Sakaarans and Nebula, who shoots down Gamora's pod.

Rocket, despite not wanting to see Gamora suffer, realizes that there is nothing they can do and urges Quill that they have to return to Knowhere, as the pods aren't meant to be out on space. However, Quill is not willing to see Gamora die in space. He goes to her and places his helmet on her head as Rocket yells for Quill to return to his pod, fearing that he will die in seconds. Yondu locates Quill and Gamora and brings them on his ship. Going back to Knowhere, Rocket proceeded in blaming Drax for Quill and Gamora getting kidnapped by the Yondu Ravager Clan. Despite this all, Rocket, Groot and Drax team up to rescue their friends off the Eclector by threatening to drive a wedge in the ship if Yondu didn't hand over their companions. Despite the odds, Rocket soon joins in on Quill's plan on taking the orb back, despite their chances. As Rocket helps the Xandarian pilots and the Ravagers fight Ronan by trying to stop the Dark Aster for landing. Ronan, however, kills the entire fleet. Rocket prevents the Kree maniac from killing his friends by running the M-ship through the ground, which knocks Ronan off his feet but knocks Rocket unconscious.

Quill picks Rocket up and carries him to safety, where Groot forms a cocoon around his teammates. Rocket goes to Groot and asks in desperation why he is doing this. In his final moments, Groot gently reached to Rocket, who was crying, comforting him with "We are Groot." After recovering, Rocket found that Groot had been destroyed, sacrificing himself while protecting his friends. In anger, Rocket attempted to attack Ronan but he had been blasted away from the Power Stone. Quill distracted Ronan with a dance off as Drax and Rocket use what is left of the Hadron Enforcer and blast the Infinity Stone out of Ronan's hammer. Watching Peter take the stone and ripping him slowly apart, Gamora, Drax and Groot join hands with Quill in order to save him and kill Ronan the Accuser. After Ronan's death, Rocket holds a sapling from Groot and begins crying but he is comforted by Drax.

He planted Groot's sapling with Rocket's criminal history expunged. Rocket joined his friends in the cosmos, with his new family and baby Groot reawakening.

Avengers: Endgame
Rocket is one of the heroes who go through the Quantum Realm in bringing everyone who died in the snap back to life by joining the Avengers. He and Thor go to Asgard, where they successfully extract the Aether (Reality Stone) from Jane Foster's body.

Groot
Rocket and Groot have been best friends since they met each other on Halfworld and began a life of crime together. While Rocket was cruel to everyone, he had a soft spot for his best friend and fellow partner. However, Rocket sometimes called Groot "an idiot" (something he later regretted after Groot saved their lives on the Dark Aster.

Peter Quill
By the sequel, Rocket and Peter seem to have something of a brother relationship/rivalry, as both of them fought over control of the Milano. However, Rocket appears to have taken the role of being Quill's co-pilot. After Ayesha insulted Star-Lord, Rocket did so as well in retaliation for the way she talked down to Quill. During Yondu's funeral the two of them seemed to have buried the hatchet, as both of them are finally seen not shouting at each other like they did through the whole movie. 

Gamora
When the two of them first met, Gamora nearly killed Rocket for kidnapping Peter while also trying to steal the Orb back. Rocket knew her as Gamora, the daughter of a genocidal maniac, and stated that everyone knows who everyone is. Both of them were forced to work together when they were tasked to give the Power stone away to Taneleer Tivan, the "Collector". Over time, Rocket saw Gamora (and Peter) as the first real friends he and Groot had. When Gamora was launched out of her pod and into space, Rocket painfully told Peter they had no choice but to leave her floating out in space, knowing that her mods should keep her alive a bit longer. He immediately blamed Drax for getting Quill and Gamora kidnapped by the Ravagers in the first place but later worked together to save their friends from Yondu Udonta.

The two seem to have gotten closer in Guardians of the Galaxy Vol. 2 and have a brother and sister relationship. When Rocket mercilessly says, "That's what you get when Quill flies," Gamora immediately threw something at him rather than Peter, saying they had to make out of this alive. Gamora did berate the two men for fighting rather than cooperating and stated that nearly one of them could have got them killed. However, Gamora did get mad when Nebula kept calling Rocket a fox.