How do stars at different stages in their life cycle appear on the HR diagram?

On the Hertzsprung-Russell (HR) diagram, stars at different stages of their life cycle are represented in distinct regions. Main sequence stars, which are in a stable phase of hydrogen fusion, occupy a diagonal band from the upper left (hot, luminous stars) to the lower right (cool, dim stars). As stars evolve, they move off the main sequence; for example, red giants appear in the upper right, while white dwarfs are found in the lower left. The diagram effectively illustrates the relationship between a star's temperature, luminosity, and evolutionary stage.