|For the Sigma Palace in Mega Man Maverick Hunter X, see Sigma's Hideout (Mega Man X).|
- "Defeat Sigma: the cause of this whole situation."
- ―Stage description, Mega Man X8
Sigma Palace (シグマパレス Shiguma Paresu) is the last stage from Mega Man X8, an ornate palace built on the Moon. After defeating Copy Sigma in Gateway, multiple more Sigmas are detected, and the Maverick Hunters realize that the true Sigma is still alive. Upon arrival, Sigma blocks the Hunters' support from their Navigators. They storm the palace and face Vile V for the last time, who pilots a Devil Bear and, depending of the game's difficulty, holds back one of the two Hunters. The remaining Hunter continues, eventually coming upon the true Sigma in his throne room. The other Hunter returns to the rescue and together they defeat Sigma. After Sigma's death, Lumine reveals his true evil intentions and attacks. They defeat Lumine as well, before heading back to Earth.
Although the fortress during gameplay and standard cutscenes is shown to have lighted hallways and rooms, the FMV cutscenes depict it as completely dark, which is especially evident with the scenes involving Lumine.