Stanford Pines, also known as “Sixer” or “Ford,” is the deuteragonist of the book, serving as Bill’s foil and the mentor figure to the reader as a character. He is the antagonist of Bill but the implicative protagonist to the intended audience, who would know that Bill is a villain. Stanford is characterized through his journal entries scattered throughout the book; most of these are warnings to the reader to reconsider interacting with Bill, but some are the “lost” journal entries that Stanford burned due to his humiliation at failing in personal relationships.

Stanford is lonely, intelligent, and conceited. Having been isolated and mocked much of his life for having six fingers on each hand and separated from his twin brother since their late teens, he believes nobody in the world truly can understand or appreciate him. This makes him a prime target for Bill’s manipulation, although Stanford is shown to be capable of great kindness and love with a desire to protect and care for others, even though his ambition often overwhelms him. Stanford’s pride and loneliness are much like Bill’s, but unlike Bill, Stanford is a dynamic character who grows over the course of the narrative. Stanford is presented in the journal entries from his youth as arrogant; he is convinced nobody except Bill understands him until far too late. He then suffers Bill’s abuse until finally reaching out to Stanley for help.

In the present, Stanford still struggles with these flaws and with the aftereffects of Bill’s abuse. He is terrified of The Book of Bill and treats Bill extremely seriously. He grows with the help of his family, however, who all treat the book (and Bill by extension) as a ridiculous attempt to trick them. This helps Stanford come to terms with his shame and accept them as a support system that can always overpower Bill. Stanford’s acceptance that he makes mistakes and needs others to help him directly parallels Bill’s refusal to do the same. This demonstrates their ultimate difference: Stanford and Bill have the same flaws, but Stanford allows himself to change and grow, while Bill remains a petulant child, determined to get his way at any cost.

Fiddleford McGucket, referred to as “Old Man McGucket” or, in Stanford’s journals, just “F,” is a secondary character and antagonist to Bill within the book. McGucket is portrayed very differently in the past and present due to his extensive abuse of his Memory Gun throughout his life. While the book does not discuss it in detail, other materials (such as the show and the published version of Journal 3) reveal that McGucket was pulled into Bill’s portal briefly and saw extensive horrors within, after which he erased his memory so often that he lost his identity and mental stability. Present-day McGucket is unstable, traumatized, and irrational, with a mind so full of pain it hurts even Bill, while McGucket in the past—seen through Ford’s journals—is kind and rational but still forgetful and sometimes thoughtless.

McGucket is portrayed as a stereotypical “hillbilly,” particularly as an old man, with a long beard, baggy clothes, and hat. Unlike the stereotype, however, he is intensely intelligent and a brilliant inventor. McGucket is primarily characterized throughout the book as Stanford’s best friend, but Stanford’s ambition and Bill’s manipulation lead to him leaving, afraid of what Bill’s portal will do and afraid of his own memories. McGucket is married but regularly forgoes time with his wife and child for Stanford, destroying his marriage and seemingly leaving him completely alone after he leaves Stanford for good. Thus, McGucket is a tragic figure; he never directly interacts with Bill but is so deeply affected by him that his life is ruined, and even his mind is too fractured for Bill to enter. This reveals the full extent of Bill’s capacity to hurt others—even those who are not his intended victims become victims from the effects of his abuse.

Thurburt Waxstaff Mudget III and the other Anti-Cipherites take up a larger portion of the book than many other minor historical figures, who are briefly mentioned and undergo no arc. Unlike them, the Anti-Cipherites—Thurburt in particular—do grow and change over the course of the recollection, even if that growth is negative. The Anti-Cipherites are characterized as collectively peculiar, traumatized, and stubborn people, driven by a desire to be freed from Bill’s influence more than anything else. They are also, to an extent, driven by guilt; all of them have taken a deal with Bill and allowed him to influence their lives. The characterization of the Anti-Cipherites is deliberately exaggerated and dramatic, with their dialogue written with a faux old-timey feel to characterize them separately from anyone writing in the modern day and to make Bill’s modern, mocking tone distinctive.

Thurburt’s growth across the brief narrative is unrealistic yet tragic. His single-minded determination to get rid of Bill leads to his downfall as he pursues increasingly foolish (although seemingly appropriate for 1901) methods to get rid of him, including an incomprehensibly complex suit and tonics more likely to poison than cure someone. Thurburt eventually ends up thrown into a psychiatric ward for his claims while his friends all go their separate ways. His character arc proves that Bill’s damaging effects go far beyond hurting those who accept him; Bill can, and will, seriously harm those who try to reject him.