Anastasia Rising in Life Memorial Day (アナスタシア立身記念日) is a shop exclusive limited edition short story. This was later adapted and included in the Re:Zero Ootsuka Shinichirou Art Works Re:BOX.
One day, Ricardo Welkin was passing by down an alleyway, where he spotted four slave traders trying to capture a young girl with purple hair. Ricardo successfully prevented them from stealing off with the girl and killed all four of them.
After sitting down with the girl, Ricardo was surprised by how fearless and resolute she was, and saw great potential in her. He found out that Anastasia was a street urchin with nothing to her name and decided that he would take her from the streets and get her a job.
As they talked, Anastasia broke down into tears; not because of what had just happened or the harsh reality of life, but because she saw that Ricardo was still forced to wear his slave collar.
After Anastasia was cleaned up and introduced to her job, the two of them had a last conversation before parting for a while. Ricardo mentioned to her the importance of putting in hard work, if she wanted to see any results. Anastasia concurred and pledged that she would come to remove his collar one day. Ricardo would remember her pledge from that moment on.