* StrawmanHasAPoint: In the second ''Death World'' book, a major character exists solely so the AuthorAvatar can explain to him the virtues of moral relativism. Only problem is, while the character is a dog-kicking DesignatedVillain, the arguments he makes against relativism aren't really shot down, just ignored in favor of the main character being made to look much cooler than him.
* MrExposition: Harrison uses characters for this from time to time, most obviously in ''Starworld'', where the Reverend Montour serves solely to flesh out and further explain the true past of the Earth that the main character first learned of in ''Homeworld''.