A spin-off series based on KonoSuba called: An Explosion on This Wonderful World! has been announced.
The spin-off series follows the early years of Yunyun and Megumin, members of the Crimson Magic Clan. Viewers will get to watch Megumin begin her “mastery” of explosion magic in the years before the main series.
— アニメ『このすば』公式ツイッター (@konosubaanime) May 28, 2022
You can read a summary of the series from MyAnimeList below.
Crimson Magic Clan members Megumin and Yunyun are at the top of their class, but they still have a lot to learn. Yunyun’s begun learning advanced magic, but Megumin has gone down a different path-the path of explosion magic! Despite being warned of its limited usefulness, Megumin believes explosion magic is the way for her to become a great, voluptuous wizard, and she won’t be convinced otherwise!
A release date for KonoSuba: An Explosion on This Wonderful World! has yet to be announced.