So you have a Cool Sword, An Axe to Grind, or another bladed/ Energy Weapon that is absurdly sharp. Sweet! Now nothing can stand in your way, not even adamantium-mithril alloy bulkheads! ...except for another, equally sharp weapon made of the same material, technology or by the same smith. Why? Well, maybe your Laser Blade's containment field is naturally blocked by your opponent's. Maybe they're both so darn sharp neither can cut through the other? Perhaps the magic behind the Empathic Weapon recognizes a sibling and refuses to harm it (or neither is strong enough to harm the other)? Whatever the case, neither weapon will break, and only a direct hit on the opponent will end the duel... which is also likely to kill them unless your Implausible Fencing Powers are good enough to disarm them without, y'know, "disarming" them. Needless to say, a character who thinks they have a Disc One Nuke in the form of their sword will be very unpleasantly surprised when facing an opponent who can even the odds. They may even get whooped if they've let their skills get rust by rellying on weapon's power. Such duels tend to prove suitably epic. Anime and Manga
- Battle Angel Alita: Last Order manga. Monomolecular wire can be stopped by a stick made out of monomolecular material.
- Gourry's energy blade sword in Slayers is eventually tested against another weapon that was created by the same people. When the two energy blades meet, they shriek.
- The energy discs in TRON and TRON: Legacy can cut through programs like butter, but will rebound off each other harmlessly.
- Light Sabers in Star Wars have this property, along with bouncing back blaster bolts. Only a small set of non-saber weapons can effectively parry them.
- n X-Men United, Wolverine and Lady Deathstrike both have the adamantium claws/fingernails.
- In the Wolverine Origins movie, it's said that the only way to stop a rampaging Wolverine, whose skeleton was newly infused with adamantium, was to use adamantium bullets. When he does get shot with one, as per this trope it's not enough to kill him, but it does give him amnesia.
- Shardblades in The Stormlight Archive can cut through any non-living substance except other Blades and Shardplate as easily as swinging them through the air (they pass straight through living flesh without leaving a mark, but kill the victim anyway).
- Shadowrun. To stop monofilament attacks (e.g. a monofilament sword), wear armor/clothing with monofilament threads woven into it.
Hello, Unknown Troper. You'll need to get known to lend a hand here.