The History that shrouds Dagobah one the most important Star Wars Planets in the original trilogy and Canon is where Master Yoda resides after the events of Order 66 sent him into exile. Yoda trains Luke on Dagobah extensively to prepare him for his duel against Darth Vader. Later Yoda after 900 years finally passes and becomes one with the force and becomes a fore ghost like Obi-Wan Kenobi.