The artist had to delete his old galleries on Pixiv, due to the guidelines and uploaded them now in new Collection.

Here is the Pixiv link to the collection:
https://www.pixiv.net/en/artworks/104892244

The artist says that all his works are free and freely available, but if you still want to give him a little support:
https://www.buymeacoffee.com/ManicoCoffee