Our universe dies due to entropy, so what do humans do best???
COLONIZE!
A near sentient AI found a way to cross realities and because our universe was dead, everyone took the chance.
They (about 100 remaining humans and a small computer) found themselves naked and afraid, in a fantasy world where they could only bring their bodies, not their clothes and certainly not their weapons.
The group first made clothes out of sheep’s wool they stole from a quiet farm. Then they made their way into a city where they saw a hero being paraded around. The AI which contained the entire history of the last universe recognized the boy as coming from the 21st century Earth.
Asking around (a bit difficult considering their language was a mixture of cyrillic and kanji) they found out that each kingdom had a hero with varying levels of power. Some had the power to level a town, while others were just good politicians.
There were also other species, they too could level a town.
The group didn’t want the attention of the kingdoms for now so they set out to build a city for themselves. They found an empty volcanic crater full of minerals and elements. They also took with them some of the time’s tools, which were just hammers and wheels and such.
So there’s a supergenius AI which knows all and a group of 100 genetically modified, immortal people, all with the same goal to conquer the world! How long would it take for this group to get to the modern or even sci fi civilization they were at? This is assuming they won’t use magic to help their tech.
This group will only consider it safe to reveal themselves once they have attained nuclear weapons. Though they probably might accidentally meet a few friends along the way.
They’ll secretly infiltrate kingdoms with their superior technology and “culture”. “Oh wow let’s eat at this restaurant the food is really good”, “There’s this place called the ‘convenience store’ truly marvelous!” “Have you heard of the new leader of his Majesty’s army? Truly a wonderful guy, his moves are out of this world” all of this happening while they slowly rebuild their super society.