Interesting, the chapter itself doesn't explain it which I think its weird, but the chapter makes sense when you read the title
"The Heroines of a Gal Game Who Avoided the End of Death Read My [Diary] And Found Out My Secret"
Thanks for the chapter!
Gonna be hard not to see the characters from this artist's other works.
This manga might be a challenge for the artist to draw characters more menacingly, since this story is (supposedly) quite dark at times.