The Immortal Confinement was brought to the Soaring Immortal Sect by Immortal Emperor Fei. Generation after generation, geniuses of the Sect entered the Immortal Confinement to test themselves, but the only one who successfully left was Can Long during his youth.
Ren Xian's sons
When Immortal Emperor Ren Xian's children attempted to reawaken their bloodline of Ancient Ming, Dark Crow attacked the Soaring Immortal Sect to stop them. They escaped and imprisoned themselves in the Immortal Confinement to hide from Dark Crow's wrath.
The Immortal Confinement is a powerful item that can confine anyone; it is virtually impossible to escape alive from it.