A teaser image featuring two or three new characters was revealed on the Witch Spring official Naver community early August 2018 before being replaced shortly afterwards. The Games page on Kiwi Walks' website was also updated to feature a placeholder image listing Witch Spring 4 with a 2019 release date.
On August 31, 2018, the new protagonist Mochamori's concept art was revealed, illustrated by series developer Suyoung Jang. On Naver, he stated "her outfit should give you an idea of what her weapon will be."
On October 6, the Japanese iOS App Store featured the Witch Spring series and released two teaser images of Mochamori, one with the full art featured in the teaser banners, and one of her in-game appearance. It also briefly mentioned that Mochamori is the queen of Ürphea who is gathering certain materials in order to resurrect her father and control the world. Later that month, the main page on Kiwi Walks' website was updated to feature her art, and the game page was updated to add chibi art of her.