From D&D Wiki
Unica was inspired by the popular video game series Fallout, as well as Studio Ghibli’s phenomenal movie Castle in the Sky, the book series the Wheel of Time and the Dark Sun and Orizon D&D Campaign Settings. Special thanks to Lemiel14n3, for having Orizon organized how he does. I'm basing how Unica's Wiki page is formatted from his
For an era estimate, I would say Late Medieval times, but with obvious differences.
This setting accommodates various alternate races, subraces, classes, class archetypes, and spells for PCs. Not all of these are significant, but add a fun bit of flavor. For the DM, it incorporates lots of creatures and spells that if not handled well can result in dead PCs. Handle with caution.
Swords and Sorcery The entire world is scarred from magic, and most of the powerful have some form of it, both the evil and the good
After the End The Spell happened long, long ago, and it's effects continue to shape the world today
A variation of I Love Nuclear Power, not being nuclear power but the ongoing exposure to the wild magic, giving people powers or creating new creatures
Apocalypse How, the Spell being a stage 5 in scope and a stage 3 in severity, killing most plants and animals and such on the planet, as well as isolating it from the other planes
Lost Technology That of Unica and whatever came before the Spell
Neglectful Precursors Seriously, who thought it was a good idea to cast the Spell? Obviously, the Neglectful Precursors!