Mario rescues 7 Star Spirits in the original Paper Mario. These powerful star beings are imprisoned by Bowser after he steals the Star Rod and uses it to become invincible.
The Star Spirits are central to the game's plot rather than optional collectibles. Each one is held by a different guardian or villain, so Mario must travel through locations such as Koopa Bros. Fortress, Dry Dry Desert, the Forever Forest region, Lavalava Island, Flower Fields, and the Crystal Palace. Defeating the relevant boss frees another spirit and advances the story.
Once all seven are rescued, their combined power allows Mario to counteract Bowser's stolen Star Rod during the final battle. The number is easy to confuse with other Paper Mario quantities: Mario has eight partners in the original game, while later entries use different star-related objects. Paper Mario: The Thousand-Year Door, for example, centers on seven Crystal Stars rather than seven Star Spirits, making “seven” correct in both games but referring to different story elements.