How Did Someone from Another World End Up in Kivotos?

This is a crossover fanfiction between the games Genshin Impact and Blue Archive, and the novel A Certain Magical Index.

A school called Abydos in Kivotos is about to close because of its debts. To save their school, its five remaining students form the Closure Countermeasures Committee to pay them off. But one day, a boy calling himself Siming appears in the desert on the edge of the school's territory. After that, their peaceful lives are completely upended, and the story takes a different course because of this boy! Academy City, the Roman Orthodox Church, Teyvat's Snezhnaya, and countless other forces, each with their own agendas, become entangled! Color, the Abyss, and even greater threats descend upon Kivotos! As these events unfold, the secrets surrounding Siming gradually come to light...

(Note 1: The story contains many hand-drawn illustrations. Enjoy!)

(Note 2: It's fine if you aren't familiar with some of the original works. Most of this story is original, so it won't affect your reading.)

(Note 3: This story will contain a lot of original plot. The first few chapters have less original content simply to set up what's to come. If some parts of the setting later don't match the original works, it's probably because the source material hadn't reached that point when I was writing the outline. You can think of it as a parallel universe.)

(Note 4: This will be a long-running work. Whether or not you enjoy it, I hope you'll leave comments. I'll humbly accept suggestions and criticism alike and make improvements in future updates. Thank you, everyone!)