Daily life in the comics: The opening scene of the demon-slayer girl

I thought I was watching a sweet, everyday anime series.
Yukinoshita Yukino, Kasumigaoka Utaha, Shinomiya Kaguya and others all appeared.
Get ready for a sweet romance.
But I didn't expect that Sadako, Kayako and others would appear one after another.
What does this urban legend mean?
Fortunately, the system has awakened.
"Extract: Five Thunders Righteousness!"
"Extract: Shangqing Dadong Sutra!"
"Extraction: Golden Light Spell!"
",,,"
They are all ready to bid farewell to ordinary life once and for all.
But I didn’t expect that those anime heroines would get closer and closer!