Pom Klementieff explains how Mantis has grown in Guardians of the Galaxy Vol. 3 since telling Peter Quill that they are siblings. Mantis met the Guardians in Guardians of the Galaxy Vol. 2 while being used by Ego to sleep, but she eventually helped them destroy the monstrous being and joined the team. After joining the team, she helped them protect the universe, bonding with Drax and Peter after telling him about their shared father.
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