Marc Anciel is a student at Collège Françoise Dupont.
Like Juleka, Marc is very shy and nervous around others. This is shown when Marinette pulls Marc into the art room to introduce him to everyone. He is also quite shy in front of his first friend at the school, Marinette, refusing to show her his stories. He likes to write stories (particularly about Ladybug and Nathaniel) but is sheepish and self-conscious when people read them. When he runs away in embarrassment out of the art room, he drops his notebook and Marinette picks it up and reads it. When she hands the notebook back to him later on, Marc immediately turns red. Like Marinette, he is clumsy and kind.
- Marc made his first appearance in "Frightningale" as a dancer for Clara Nightingale's music video alongside Nathaniel, Mylène, Ivan, and Sabrina.
- His first name was revealed in a UK episode synopsis on May 19, 2018.
- His akumatized form was first seen in a photo taken by Jeremy Zag of the show's production for Season 2.
- On May 21, 2018, Thomas Astruc revealed on Twitter that a (at the time unspecified) character was based on a personal friend of his named Hope Morphin, who is genderfluid and bisexual. A few hours after "Reverser" premiered on Family Channel, Morphin themself revealed that the character Astruc was referring to was Marc, and also that Marc is androgynous. Feri González confirmed this, and also later confirmed on Twitter that Marc identifies as part of the LGBTQ+ community and has "fondness" for Nathaniel.
- Marc's full name, Marc Anciel, is a play on the French word "arc-en-ciel", which translates to "rainbow" in English. This wordplay both references his multicolored outfit and his being a part of the LGBTQ+ community.
- Hope Morphin has confirmed that Marc's three favorite animals are the sheep, peacock, and goat.
- His visible eyelashes and pink lips may imply that he wears makeup.
- Reverser appears another time in "Gamer 2.0" for Gamer's powers.