Kundera's characters are often explicitly identified as figments of his own imagination. Kundera is more concerned with the words that shape or mould his characters than with the characters' physical appearance. In his non-fiction work, The Art of the Novel, he says that the reader's imagination automatically completes the writer's vision. He as the writer wishes to focus on the essential. For him the essential does not include the physical appearance or even the interior world (the psychological world) of his characters.
François Ricard suggested that Kundera conceives with regard to an overall oeuvre, rather than limiting his ideas to the scope of just one novel at a time. His themes and meta-themes exist across the entire oeuvre. Each new book manifests the latest stage of his personal philosophy. Some of these meta-themes are exile, identity, life beyond the border (beyond love, beyond art, beyond seriousness), history as continual return, and the pleasure of a less "important" life. (Francois Ricard, 2003)
Many of Kundera's characters are intended as expositions of one of these themes at the expense of their fully developed humanity. Specifics in regard to the characters tend to be rather vague. Often, more than one main character is used in a novel, even to the extent of completely discontinuing a character and resuming the plot with a brand new character.