The Infernal Devices Redesign Book Spine

The Infernal Devices by Cassandra Clare : September 2015 reissue (spine art)

My personal favorite: have them die in a necessary danger that was created by the protagonist to eventually bring down the antagonist

Make the book sum up. And then on the last page kill the most lovable character by the main protagonist and the protagonist likes it. How to make a characters death sadder