They play an important role in the story, whenever a character manages to get one of these they can:
+ Gain a temporary access to the NEXUS, the place where countless of realities converge at the same time.
+ Allow you to travel to the universe of your choice.
+ Summon temporarily Clavis Angemon´s hoy Key if you have at least 10 thousands of LF + a pair of Holy Rings
But once a Key´s used, it will vanish in the act. The Keys are temporal items.
To get a Key it´s required to have d some Holy Codes embedded in your system and then have accumulated a huge amount of digital Codes in your bag to summon it. The more codes you have accumulated, the longer the Holy Key will last.
The Keys also have another function, if the user is strong-willed enough he or she can invoke (albeit temporarily) the mysterious Angel of Destiny ´s presence.
But the angel SHOULD NOT BE CALLED…
Who can summon a KEY?