The Stone Sky by N.K. Jemisin
The Broken Earth Series by N.K. Jemisin are probably my favorite books I've ever read. The Stone Sky is the third book in that series.
I just truly loved them. The magic systems were interesting, they were unique, unlike any magic systems I've ever read or seen in media before.
The characters were also interesting. Usually loveable, but sometimes they made it hard.
The series starts with the end of the world - the land being split open at the equator and magma being exposed and ash shooting into the sky. This is the start of a "Season", in the book's terminology.
I don't want to yap more about it, for fear of spoiling it.
Go to your library and get The Fifth Season. It's so fucking good. And then you'll get #2 & #3 when you're done because you'll need to.