3 ideas
Read Grégoire's planned murder as a status project, not a crime of passion or rage: a nobody from a nameless slum wants the city's newspapers and gossip to finally register his existence. On this view the act is aimed at an audience, and the victim is almost incidental, an instrument for converting invisibility into fame.
Angoualima works for Grégoire as a secular saint: he visits the killer's tomb, confesses there, and receives scornful ghostly counsel that he treats as authority. Choosing a notorious outlaw as a patron shows how an abandoned person with no lineage builds a substitute father and a borrowed identity out of local legend. The idol also becomes a measuring stick that guarantees the worshipper's permanent sense of inadequacy.
Grégoire narrates in the first person with grandiose self-justification. The gap between his menacing self-description and his clumsy, fearful actions turns the monster into a figure of dark comedy and pathos. The novel suggests that the aspiring killer's real condition is not evil mastery but impotence, and that his inflated rhetoric is how he compensates for a life that grants him no agency.