Crowfall explains the Hunger that’s killing everything
The Hunger is going to destroy everything in Crowfall. That’s how the story ends. You can stave it off for a time, and the latest development post is all about how you can do that. But the point is that as the seasons change, you will lose the fight. Only a few hunger crystals might appear at night during the summer, and you can hopefully find and eliminate them. And creatures mutated by the Hunger can’t survive during the day, so they’ll be dealt with that way. You can take the land back!
But as time goes by the nights get longer. The seasons change and more crystals emerge every night. Cutting away the crystals is treating the symptom, not the disease. Eventually the place where you are will succumb to the frost and stillness of the Hunger, there are no two ways about it. The official entry goes into more detail, but that’s the short version right there. Have fun!