The City We Became by NK Jemisin

Five New Yorkers must come together in order to defend their city.

Every city has a soul. Some are as ancient as myths, and others are as new and destructive as children. New York City? She’s got five.

But every city also has a dark side. A roiling, ancient evil stirs beneath the earth, threatening to destroy the city and her five protectors unless they can come together and stop it once and for all.