User blog comment:RaijinRising/Pyrrha Foreshadowed the Deity Brothers/@comment-25936766-20170212134046/@comment-33293221-20170213013207

But you also have to realize that they had many, many worldbuilding sessions before the show started. They had to have come up with a central conflict during that time along with all the characters.

The relics are key to the conflict (because Salem's going for them). And maybe they didn't go so in depth as to what the relics symbolized during those meetings, but I'm willing to bet they did.