>>39856517Pic related. Jack the Ripper from Fate.
During the 1800s, London was rife with thick pollution, slums and notably, prostitution. These prostitutes would regularly become pregnant and have the children aborted, and this happened thousands of times. Eventually, the desires of the "children who weren't even given a chance to be born" came together to form a single entity that embodied this desire to "return to inside mother".
The entity went on to find prostitutes and do that on a literal level, killing and dismembering prostitutes to feel the warmth of mother that "they" had once felt before they were aborted. Hence, with these gruesome prostitute murders, she is Jack the Ripper.
tl;dr, she is a collection of thousands of 18th century children of prostitutes that were aborted, meaning she was never "born" and technically is negative a few months old.