Sofia Eugenia Alexander is a Mexican animator, storyboard artist and voice actress known for her work as the executive producer and creator of the show Onyx Equinox and her storyboarding for Stretch Armstrong and the Flex Fighters, Infinity Train and The Powerpuff Girls reboot.

Alexander was born in Quintana Roo, Mexico. She grew up around archeological sites such as temples from the Mayan civilization. Her grandfather was proud of their indigenous culture and saw it as something important to teach Alexander, so he often told her stories and made sure she visited archeological sites such as the temple Uxmal in Mexico. While growing up in Mexico, Alexander had access to a lot of anime as it aired on television and watched shows such as Dr. Slump, Dragon Ball, Mikan Enikki, Rurouni Kenshin, and Wolf's Rain, as did Saint Seiya, and Cardcaptor Sakura, the latter which inspired her to draw. She later said that while she was discouraged from drawing art influenced by anime, she was determined to have it influence Onyx Equinox, with the anime aesthetic appealing to her.

Alexander worked as a storyboard revisionist for 28 episodes of The Powerpuff Girls reboot series, which aired on 2016 from to 2019. She also was a writer for episode "Splitsville". This job was how she began working in the animation industry, as a freelancer. Following this, she worked as a storyboard artist for Stretch Armstrong and the Flex Fighters (2017–2018), a Netflix series. She was a storyboard artist on nine episodes and storyboard revisionist for five episodes. Alexander later said that while her work on The Powerpuff Girls was helpful for storyboarding, she had to learn to become a showrunner on the job.

Alexander is best known for her series, Onyx Equinox. Prior to its release, she described it as an "adult story" in terms of themes and action, with Izel forced to "save a world he doesn’t believe he has a place in," facing darkness in "the world and within himself." She specifically emphasized specific colors in the show, with pink and turquoise representing historical symbolism in Mesoamerica Mexico. She later revealed that she began the series as a comic strip during college, which featured a few of the show's characters, and was inspired by the Lord of the Rings, The Legend of Zelda, and Aliens, wanting something similar in Mesoamerican mythology.

She began developing the story and its cast of characters in 2007, then developed a pitch for the series in 2011, but took her years of pitching it to companies such as Frederator, Netflix, and Crunchyroll, before it was picked up. Marisa Balkus of Crunchyroll, the Executive Producer in charge of original development of the streaming service, approved the show, after Alexander pitched it in early 2018, arguing that Mesoamerican Mexican culture isn't often portrayed on television and would be interesting to portray in an anime story medium. Writing on the series began in October 2018.

The series premiered on Crunchyroll in October 2020. Alexander served as the creator, illustrator, and executive producer of Onyx Equinox. She also voiced the character K'i'ik, the weapon which "grows stronger once it tastes blood." Alexander described the series having a touch of anime combined with "truly Mesoamerican characters" and stated that the show was the result of researching ancient civilizations in Mesoamerica. She also said the series allowed to see the beauty in her own culture and heritage and said that she had the chance to be mentored by Japanese animator Kuni Tomita who also served as supervising director, with Tomita guiding her in being the head of the show. She characterized Tomita as an "animation mom" and an "empowering and incredible force" while noting that Tomita warned her against animating detailed designs of gods, saying animators will hate her for making them do it, and she justified it by saying it is important culturally. Alexander has also provided her voice for characters such as Nelli, and Meque, was a show writer, and a storyboarder for the episode "The Bet."

Alexander, in a November 2020 interview with CBR, shared her challenge with pitching the series and wanting to do it with "dignity and respect towards Mexico and Indigenous Mexicans" and said that Crunchyroll had been "wonderful to the project." She called the series a translation between her experiences "into the writer's room and into animation." She also called the series a "Mexican project," said she found many of the cast and crew from her personal collections and social media, but said that the show is not an anime, from her perspective, and called Crunchyroll a "great platform" to tell the show's story. However, in August 2020, Alexander had said that creators of animation do not have a say in the marketing of their shows. In other interviews, Alexander described the show as "a love letter to Mexico and to other Mexicans," argued that blood is a main part of the story but not something to fear, said that the show tries to introduce people to Mesoamerican myths. Alexander also said that she hoped that fans of Western animation would "see the appeal of action-drama animation for adults" and stated that the series had help from an archaeologist/anthropologist and extensive research to ensure certain aspects of the show's world are inspired by actual history.

In December 2020, Alexander was nominated at Animation Magazine's 2020 Hall of Fame Awards and won The New Voice of the Year Award for her work on Onyx Equinox.