For future reference. the character request here refers to the image on the bottom right corner of the page, which appears to be a crop of another illustration.

G-SANtos said:

For future reference. the character request here refers to the image on the bottom right corner of the page, which appears to be a crop of another illustration.

Full version of that image is here but doesn't have any character or copyright tags on Yande. I'm guessing she is an original character unless the there is something in the Japanese text I can't read.