
I think you missed a pretty big section where it explained everything. Eric had to be the scapegoat for Humpty Dumpty (a mutant art) and Jack (a vampire from the slums), so that humans and vampires could find common ground to make peaceful relations. To do this, Eric planned a shoddy play of sorts that managed to work. Eric had held up a metal plate for Shell to shoot at, which stopped the bullet from actually injuring him during the scapegoat scene. Because Eric had "died," he went to his parents' land with the white roses to live in peace while Shell and the other abnormal vampire began creating a new kind of bank with actual monetary payment to make it fair for giving blood, which was shown after a "Three Years Later" moment. But it was subtly mentioned that Shell would go visit Eric whenever he could (and when his friend was low on the good pheromones that belonged to Eric), which was shown on the last page, and they lived happily ever after—or so to speak.
Hope that made sense for you.
I’m so confused...