Mantis is a character appearing in American comic books published by Marvel Comics. Created by writer Steve Englehart and artist Don Heck, the character first appeared in The Avengers #112 (June 1973). Mantis has been depicted as a member of the Avengers and the Guardians of the Galaxy, as well as the mother of Sequoia.

Pom Klementieff portrayed the character in the Marvel Cinematic Universe in the Marvel Cinematic Universe films Guardians of the Galaxy Vol. 2 (2017), Avengers: Infinity War (2018), Avengers: Endgame (2019), Thor: Love and Thunder (2022), The Guardians of the Galaxy Holiday Special (2022), and Guardians of the Galaxy Vol. 3 (2023).

In an interview, Englehart commented on the character's creation: "I wanted someone to shake up the Avengers, so I came up with a femme fatale, but right after I did, I also came up with the Avengers-Defenders Clash, and I needed to use my femme as a solid team player, not a disrupter. I found that interesting – a character I'd created for a purpose who now had no purpose, and as a young writer exploring my parameters, I started letting her tell her own story – meaning, every issue I'd tell my overall Avengers story, with my various character developments, and things then would happen that she had to react to. Those reactions – or what I conceived her reactions to be – revealed her character for me, step-by-step, as the worlds I was definitely creating grew bigger and bigger, and in that way the femme fatale became the Celestial Madonna."

Mantis first appeared in The Avengers #112 (June 1973), drawn by Don Heck and created by writer Steve Englehart, beginning the "Celestial Madonna" saga. After leaving Marvel Comics, Englehart carried Mantis's tale through three other companies: moving from Marvel to DC to Eclipse to Image and finally back to Marvel.

In DC Comics' Justice League of America #142, she appears as Willow. Asked where she came from, Willow replies, "This one has come from a place she must not name, to reach a place no man must know." (Mantis refers to herself in the third person as "this one") By the end of the issue, she leaves to go give birth.

In the Eclipse Comics series Scorpio Rose #2, the character calls herself Lorelei. By this time, she has given birth to a son. What would have been issue #3, a "lost" Lorelei/Scorpio Rose story was later published in Coyote Collection #1 from Image Comics, the character's fourth company. Lorelei is later mentioned in Englehart's 2010 novel The Long Man (page 355, mass market paperback edition).

Mantis is the half-Vietnamese, half-German daughter of Gustav Brandt—Libra—and was born in Huế, Vietnam. In her childhood, her father leaves her in Vietnam at the Temple of the alien Priests of Pama, a sect of the Kree. The Kree believe she might become the Celestial Madonna and mate with the eldest Cotati on Earth to become the mother of the Celestial Messiah Sequoia, "the most important being in the universe".

She excels in her martial arts studies, but upon reaching adulthood, she is mind-wiped and sent into the world to gain life experience. She becomes a sex worker and barmaid in a Vietnamese tavern, where she meets the Swordsman. She helps him regain his self-respect and follows him when the former villain attempts to rejoin the Avengers. She becomes an Avengers ally when the Swordsman rejoins the Avengers, and she battles the Lion God alongside them.