When George walks onto the field in New Hampshire, the people who know about the Spikes (all of them shortswords) know that he's got the Midnight Spike when they see his red and black sword. They might not know what it does, or they might have heard the stories. When people see Gary walk out as Galloway with the Sun Spike in his hand, they probably know it's a big deal if they've played the chapter before. (Especially if you've been around when Cerulean was out, aka Samara in dragon makeup.) Same, in the chapter, with Void and Puriel. They are super-powerful Artifacts whose story is pre-established in the history and lore of the land, thanks to the work of the plot team.
Those weapons, in that place, are mythical. Because there isn't an established world history, with established world figures who have done well-known deeds, it's hard to make items that can be recognized Alliance-wide. There isn't a Ghengas Khan, a Roman Empire, a Cleopatra or Shakespeare or Napolean of Fortannis, because super-famous figures and the legends that spawn from them don't spread from place to place unless it's PCs retelling the story, or the uber-rare NPC that mist travels.
