Strange things starts happening in the Fujiwara household, and Takashi Natsume suspects a yokai might be hauting the house. His doubts are confirmed once his foster father, Shigeru, tells something similar happened before when he was a child, and Natsume's mysterious grandmother, Reiko, seems to be related to this story.
Yuki Midorikawa's afterwords illustration of Chapter 19.
"I first considered Reiko to only be the setup and the punch line to the story, but more people were interested in her than I expected, so I did a proper story involving her. I knew what Mr. Fujiwara would be like, but I thought it added flavor when he was only alluded to, like Columbo's wife. And I didn't really have space to fit him in before. So this was a good opportunity. Is Natsume unable to be like Reiko, or was Reiko unable to be like Natsume? It makes me think."
This is the third time Reiko Natsume features in a story and chapter (through flashback).
Although Natsume's Book of Friends started getting serialized in LaLa magazine with Chapter 16, this chapter was exceptionally published in LaLa DX like the ones before it.
Yuki Midorikawa said she had to work on Chapter 19 at the same time at the same time as Chapter 17-18, which overworked her.
Midorikawa said this is the first time she decided to make a proper story about Reiko because of how many people got interested in her, when initially she was only supposed to be the "the setup and the punch line to the story."