User blog comment:Roranoa Drake II/Episode 725 Review: Road to Gear Fourth/@comment-24850639-20160111190801/@comment-2226235-20160112063808

It's taking from the same source as the 36, 72 and 108. The concept of earthly desires and the number 108 are both important in Buddhism, although I don't know the exact details. Wikipedia has a decent explanation for where that comes from.