Adam Warlock's introduction in two different teases in the Guardians of the Galaxy movies, Adam Warlock might finally arrive in Phase 4. Whether his encounter with the Guardians is a friendly one or ends up in a catastrophic battle, Warlock's presence will affect the whole MCU due to his tremendous power level, but in particular, Rocket Raccoon.
Rocket Raccoon is a 3-foot-tall "trash panda" with a penchant for guns and cybernetic prostheses and his backstory is a painful one. That goes for both the comics and the live-action movies. But despite his diminutive size, Rocket has fought Ronan the Acc, Ego the Living Planet, and Thanos in the movies and lived to tell the tale, defiantly trash-talking the entire time. However, his brash personality hides a lot of pain. Rocket Raccoon's tragic MCU origin story may be explored in Guardians of the Galaxy 3, and Adam Warlock's birth can make for a good thematic echo to the Guardian's past.
Rocket Raccoon has alluded to the horrors of his creation in both Guardians of the Galaxy movies. So far, it's known that he was genetically and cybernetically engineered to become anthropomorphic. He once mentioned how he was "torn apart and put back together over and over," which appears to have originated his aggressive impulses – it would make anyone angry and abrasive. This trauma can be shared by Adam Warlock, who was created and is currently being held by the Sovereign, a genetically engineered race of aliens, as a backup weapon with no regard to his feelings, personality, or freedom.
As the Sovereign leader Ayesha describes her people, "every citizen is born exactly as designed by the community. Impeccable, both physically and mentally." Adam Warlock is designed to be the epitome of their perfection, regardless of his own aspirations. Warlock could rebel against his creators and embark on a quest for identity in Guardians of the Galaxy 3, prompting Rocket Raccoon to do the same if he meets the people who tortured him and made him what he is.
The previous two Guardians of the Galaxy movies have explored the theme of identity and family, both biological and found: Guardians of the Galaxy Vol. 1 chronicled how a group of oddballs found a family in each other despite their differences. Guardians of the Galaxy Vol. 2 tackled it through the lens of heritage, legacy, and family with Star-Lord learning the truth about his parents and Gamora making peace with Nebula. Now, Guardians of the Galaxy 3 can continue diving into the depths of identity by questioning how Rocket Raccoon and Adam Warlock deal with their individuality in spite of their artificial creation as living weapons.
Adam Warlock could have interesting interactions with characters like Thor and the Eternals, but Guardians of the Galaxy Vol. 3 is the right movie to establish his thematic foundations before that. Besides the danger he may present to the Guardians, his story can give Rocket Raccoon and his friends a deeper look at their own psyche.
