Constance Verity Destroys the Universe by A. Lee Martinez

The third and final book of Constance Verity's epic adventure in which saving the world is easy-everything that comes after is the tricky part. The Adventurer. The Great Snurkab. The Caretaker. Constance Verity returns, having accepted and secured her place in the universe while juggling her expanded life. Until she comes up against The Caretaker's nemesis, a foe she can't just beat the hell out of, Connie must defeat the idea of inevitable entropy, the end of everything. Impossible you may think, but Connie always has an angle, and this time it's by upping her game, by stopping enough calamities, by answering every tug at her innate sense of adventure, she can build up enough power to counteract the end of the universe. The problem is, she's still a human woman, and even she can't keep this up for long. As she starts to fade her friends figure out a way to help- Destroy the world.