In the Jack the Ripper story, Jack the Ripper was a very infamous figure. He preyed on women in a poor area of London. There have been many suspects proposed over time, from local butchers to members of the upper class trying to cover up some sordid secrets. But no one has been definitively proven to be him.
Well, it's rather inappropriate. The Harry Potter universe is about magic, friendship, and heroism. Jack the Ripper represents a completely different and very dark aspect of human history. Mixing the two seems like a disrespect to the original themes of the Harry Potter series and also a rather morbid idea in general.
An OC (Original Character) in Fate Apocrypha fanfiction can bring fresh perspectives. It allows fans to explore uncharted territories within the Fate Apocrypha universe. For example, an OC could be a new Servant with a unique backstory and abilities, which might interact with the existing characters in interesting ways. Fanfiction writers often use OCs to fill in the gaps they feel exist in the original story or to create their own unique story arcs that still fit within the overall theme and lore of Fate Apocrypha.
Jack the Ripper was indeed a real phenomenon. Although the identity of the perpetrator was never conclusively determined, the series of brutal murders that took place at that time are well-documented and considered a factual part of history.
Jack the Ripper is based on real events. However, some details and theories about the case might be speculative or fictionalized over time. But the core of the story is rooted in actual crimes.
Maybe some people just want to be edgy. They think by combining such a well - known and positive franchise like Harry Potter with a dark and infamous figure like Jack the Ripper, they can create something unique and shock - value - based.
Another concept is a more comical crossover. Shirou tries to adapt to the different rules and magic in the Fate Apocrypha world. He constantly gets into funny situations as he misunderstands the local customs and magic systems. For example, he tries to cook using Apocrypha - style magic ingredients and chaos ensues.
One popular trope is the 'hidden power' trope. The OC might start off as an unassuming character but gradually reveals a powerful and unique ability that changes the course of the Holy Grail War. Another is the 'love interest' trope, where the OC becomes romantically involved with one of the canon characters, adding a new layer of drama to the story.
Jack the Ripper's origin story is clouded in mystery. It was around the late 19th century in the Whitechapel area of London. He targeted mainly female prostitutes. Some believe he could have been a disgruntled former patient of a mental institution who was released and took out his frustrations on these women. Others think he might have been a member of the upper class trying to cover up some sort of scandal by killing these 'undesirable' women. But again, all of these are just theories.