Final answer:
The narration shift to Rahim Khan in 'The Kite Runner' provides essential insights and perspectives that Amir cannot deliver, enriching the plot and character development.
Step-by-step explanation:
The narration shift from Amir to Rahim Khan in The Kite Runner is an essential narrative device used to provide a different perspective and deliver crucial information that the protagonist, Amir, is not privy to. This shift occurs because it allows the reader to learn about events and motives from Rahim Khan's viewpoint, which ultimately enriches the understanding of the plot and character development. This narrative technique also enhances the depth of the story by showing the impact of past events on different characters, and by illustrating how individual stories interweave within the larger narrative.