[[File:Greater-rift-keys-ptr2.JPG|left|thumb|90px|GRKs.]]

Initially in Patch 2.1 testing, level 1 GRKs were dropped directly by Nephalem Rift Guardians. That system was changed to have those monsters drop [[Keystones of Trials]], which enable players to endure wave events in the Realm of Trials. Defeating more waves will earn higher level Greater Rift Keys. A Greater Rift Key is also awarded by Greater Rift Guardians, if players defeat it within the 15m time limit. That GRK will always be at least 1 level higher than the Grift it was earned on, and can jump up to 9 levels higher depending on how far ahead of the 15m timer players complete it.