Artist:
https://www.patreon.com/SadBag
https://www.pixiv.net/en/users/107450265/artworks

The artist had deleted his Deviantart account.

Every part has a description in it's original post that gives more context.
1- https://www.pixiv.net/en/artworks/138386147
2- https://www.pixiv.net/en/artworks/138416601
3- https://www.pixiv.net/en/artworks/138481252
4- https://www.pixiv.net/en/artworks/138560383
5- https://www.pixiv.net/en/artworks/138690481
6- https://www.pixiv.net/en/artworks/138799129