Mantis, played by French actress Pom Klementieff, joins up with the Guardians after Quill's biological father, the celestial being Ego, introduces her to them. She realizes that she no longer wants to help an evil, egomaniac take over the world.
Her abilities include sensing others' emotions and feelings. She can also induce sleep and manipulate others' feelings. She uses her abilities to defeat Ego, and Thanos.