17. Harold MacDougal
Harold MacDougal was an eccentric (read: racist drug addict) who featured in the closing stages of Red Dead Redemption. He's a professor from Yale who sets out to 'study' the Native American populace, though only in the interest of furthering his own bigoted perspective.
MacDougal doesn't actually make a physical appearance in Red Dead Redemption 2, but he is mentioned both through dialogue and in the game's literature. Purchase an issue of the New Hannover Gazette, and you'll see an advert for his new book.