An atmosphere similar to Earth's made Intai'sei an early candidate for human colonization. However, prohibitively high temperatures and an arid climate have proven a hindrance to terraforming and agriculture. A few human cities were founded, but the majority of the human population on Intai'sei remains scattered across the vast deserts, operating wind farms and geological research stations.
- Mission: Citadel: Kakliosaur Fossil
- Assignment: Pinnacle Station: Convoy
Search and Rescue
- Main article: Search and Rescue
- Artifact: Fossilized Kakliosaur
Admiral Ahern has a retirement home on Intai'sei that he doesn't plan on using anytime soon. It's a prefab dropped by ExoGeni Corporation on a quiet and remote location. Ahern is willing to wager its ownership upon completion of his special simulator scenario aboard Pinnacle Station.
- Mass Effect, Intai'sei was added as the fifth and outermost planet in Phoenix by the Pinnacle Station DLC. However, its ingame orbital stats actually placed it between Tuntau and Sylsalto. This discrepancy was corrected in Mass Effect 3, and Intai'sei was moved from the fifth orbital of the system to the third.
- The name for the planet may be taken from the Japanese noun "intaiseikatsu" (隠退生活) which means "secluded life." Intai'sei can also be conveniently read in Japanese as 引退星 ("retirement planet").
- Intai'sei's capital, Thoreau Mesa, may have been named after Henry David Thoreau, an essayist who extolled the virtues of simple living and a balance between nature and culture.