Zig Zagged: Hiro finds the rusty sword in the first episode, and is convinced that it's the weapon destined to defeat the Big Bad. He lugs it around for ages trying to find someone worthy of restoring it, while some characters call him crazy and point out other, more powerful-looking weapons, and others quietly suggest that it might simply be a Magic Feather. Even after it's broken in a fight, he keeps Dreaming of Things to Come and pressing on with his personal quest. Eventually it's restored and discovered to be an Empathic Weapon that was secretly testing his faith, and on finding him worthy bestows its full power.
"Great, we're all set to slay anything that hasn't had its tetanus shots."
Invoked: The sword is an Empathic Weapon that disguises itself as a rusted piece of junk to attract a suitably Humble Hero to wield it.
Exploited: An "Honest John" manufacturer of cheap swords keeps them in salt water for a month so he can pitch them as being long-neglected Ancestral Weapons going for a song.
Defied: "Even if this sword was great once, it'd be ruined by all this rust!"
Discussed: "Go for the rusty old sword. I bet it'll turn out to have awesome magical powers."
Conversed: "He has to pick the legendary Dragonsbane out of the Flaming Sword hanging in mid-air, the shining silver one on a plaque on the wall, or the rusty one sitting in the fireplace? Gee, I wonder..."
Deconstructed: Hiro recognizes the Dragonsbane and, aware of its fearsome reputation, cleans the worst of the rust off and carries it into battle. However, despite his best efforts to polish it up, the years of neglect have left it brittle and dull and a shadow of its legendary reputation.
Played For Laughs: Part of the reason the Dragonsbane is so effective is because every dragon that sees it bursts into uncontrollable laughter and can't concentrate on the battle.
Played For Drama: The Dragonsbane is the only weapon that stands a chance of defeating the dragon god Marduk... But it's been lost for eons, and when finally rediscovered, is in such a state of disrepair that it's practically unrecognizable.