Setting: An Earth-like planet except all the continents are joined together like Pangea. The locals are in the medieval era and have the ability to use magic. Magic can level buildings at best, certainly not enough to leave the planet.
Population: approximately a million humans, a million elves, a billion demons, and all the other kinds of plants and animals
Problem: A super eruption similar to the ones that happened during the Earth’s Permian period. It will cover a quarter of the continents in 50 meters of lava. Any continents that aren’t reached by the lava will still be affected by ashfall, sulfur monoxide and the blocking of the native sun.
Would be saviors: 250 genetically modified, immortal humans with an intelligent AI who were transferred to the planet when their universe decayed. They too have a tech level of the medieval era as they still have to develop technology.
Preparation time: Approximately 220years, though the area that’s about to erupt is already experiencing release of steam and explosions which is how the human saviors found out about the coming eruption.
Goal: To save as many as possible.
Ps: The humans from the other universe can’t use magic so they can’t transfer the lava to the old universe. I was hoping they’d develop tech to interplanetary? or interstellar which ever works.
Also, this past question of mine goes into detail about the AI and the humans. How long or how hard is it to develop a medieval fantasy into a modern or even sci-fi civilization.?