Images on pages 2-5 are AI scaled up because the original from his blog was heavily compressed and lowerres. Sadly a lotta the detail was lost in the process (in the cropped images of their faces you can see the original detail that they had before the blog downsampled the full image).

Original images from page 6-14.

Please support the artist if you enjoy their work!
https://vincentmcart.blogspot.com/2019/03/rei-asuka.html
http://www.hentai-foundry.com/pictures/user/VincentCC/688917/Rei-and-Asuka
https://twitter.com/vincentccart/status/1112178797447659520