Brainstorming Tread about Underused Setting for Isekai Fiction

as everyone knows about Isekai Fiction. Most story is often set in Standard Japanese Fantasy Setting but if we look at the history of Isekai Fiction which starts with John Carter of Mars we often see how Isekai has so many settings

now we are brainstorming about Underused Setting for Isekai Fiction

I think that Late Antiquity & Early Medieval Fantasy Setting would be cool due we have so many events that could be used during that era from the Fall of the Western Roman Empire, the Barbarian Kingdoms, the Christianization of the Roman Empire, the Crisis of the Third Century, Rise of Islam,Viking Invasion,Conquest of Justinian etc

The 3rd Century Crisis would definitely be an interesting time to be isekai'd into.

Imagine an empire so hard up for competent manpower that they're down to summoning help from another world just to fill the ranks. Imagine being given a Centurion's job simply because everyone else available was either severely malnourished, illiterate, sick with the plague, or needed somewhere else. You're just given a month or two of crash course training and then sent to the front.

Or you're assigned as a Praetorian since you don't have any familial connections and tasked with desperately keeping the Emperor alive another day when entire aristocracy seems determined to kill him.

• Prehistoric times
• Crystalized landscape
• The Wild West
• Steam era Europe

One interesting book I read (The Transall Saga) had the protagonist get isekaied into a world with ancient politics and flora and fauna never seen before on Earth. It turned out that this world was our world, but in a future where civilization as we know it collapsed due to a nuclear war triggered by the chaos ensuing from a global pandemic.

>if we look at the history of Isekai Fiction which starts with John Carter of Mars we often see how Isekai has so many settings

I'm sorry but what? Isekai predates John Carter of Mars by literal centuries.

Nobody seems to do Urban Fantasy, Punk Punk, or sci-fi.