The Darwinian Method of Story Building.
Imbuing each character with a trait so utterly unique that tracing the evolution of said-trait back to its origin is a spell-binding story unto itself.
Of course, that spell-binder is never told.
It is a secret held by the author alone, the novel built upon the scaffolding at its side.
(Yeah, sorry. I’m giddy tonight and waxing wisdom like I own it.)