The series follows the adventures of Star Butterfly (voiced by Eden Sher), the young turbulent heir to the royal throne in the dimension of Mewni, who is sent to Earth to mellow her reckless behavior.
There, she befriends and becomes roommates with human Marco Diaz (Adam McArthur) and begins a semi-normal life in Echo Creek, attending school and meeting new friends.
Throughout the first season, the two travel to exotic dimensions using dimensional scissors while preventing the Mewman monster Ludo (Alan Tudyk), and later, Toffee (Michael C. Hall), from stealing Star's magic wand.
As the series progresses, Star and Marco fall in love with each other, meet new friends, take on new enemies, and travel to even more weird and wild dimensions.
After she accidentally sets fire to the family castle, her parents, King River and Queen Moon Butterfly, decide that a safer option is to send her to Earth as a foreign exchange student, so she can continue her magic training there.
She befriends student Marco Diaz and lives with his family in suburban Los Angeles while attending Echo Creek Academy.
As the series progresses, new, more threatening antagonists appear in the show, including the mysterious monster Toffee and former Queen Eclipsa's half-Mewman, half-monster daughter Meteora Butterfly.
Several secondary protagonists also appear more prominently or join the series in subsequent seasons, including Star's Mewman best friend Pony Head (who is a floating unicorn head), Star's half-demon ex-boyfriend Tom, the mischievous Janna, and Magic High Commission member Hekapoo; Queen Moon also takes on a bigger role.
[8][9][10][2] Nefcy originally placed Star in the fourth grade, reflecting on a time in her own childhood when she held a self-described obsession with the animated series Sailor Moon.
However, Nefcy later adjusted the character's age to fourteen during the time she made her series proposition to Disney rather than Cartoon Network originally.
[11] In addition to Sailor Moon and Dragon Ball Z, Nefcy has said that she had heavy influence in her youth from the animated Japanese shows Magic Knight Rayearth, Revolutionary Girl Utena and Unico, the last of which featured a blue unicorn.
She also cited shows unrelated to Japanese animation such as Buffy the Vampire Slayer,[7] and was influenced by independent comic series such as Scott Pilgrim and The Dungeon.
[32] The series premiered on Disney XD channels in the United Kingdom and Ireland on April 16, 2015,[33][better source needed] in Australia on August 3,[34] and in the Middle East and Africa on October 5.
Johnson stated that Star vs. the Forces of Evil "excels on wild, silly, and clever set-pieces to bring the laughs and action", but expected that adult viewers won't get much out of it.
[40] In reviewing episodes from the first season, Marcy Cook of The Mary Sue described the show as a blend of others such as Invader Zim and a sanitized Ren & Stimpy, with great appeal to tween and teen girls as well some laugh out loud moments for adults.
[43] The premiere of Star vs. the Forces of Evil became the most-watched animated series debut in Disney XD’s history with an average of 1.2 million viewers.
[44] Following the end of the second season, Disney XD announced that in 2016, Star and another animated show Milo Murphy's Law had reached over 100 million consumer views combined across its media platforms.
A comic book series titled Deep Trouble was written by storyboarder Zach Marcus and illustrated by character designer Devin Taylor, both of whom are part of the Star crew.
[59] The book Star and Marco's Guide to Mastering Every Dimension, authored by Amber Benson and supervising producer Dominic Bisignano, was published on March 7, 2017.
[66] Star vs. the Forces of Evil characters appeared in the Disney Channel original series Chibiverse which started airing on July 30, 2022.