Here's why:
* Standard Sword: Backbiter is depicted as a regular, albeit sharp, sword. It's not described as having any special features or glowing properties like other magical weapons in the series.
* Luke's Skill: Luke's expertise with the sword is what makes it dangerous. He is a skilled swordsman and a powerful demigod, making the weapon dangerous in his hands.
* Not a Named Weapon: The sword is never given a specific name in the book, unlike other famous weapons like Riptide (Percy's sword) or Annabeth's Celestial Bronze knife.
While Luke's sword isn't inherently unique, its significance lies in the fact that it's the weapon of a formidable antagonist, representing the threat Luke poses to the demigods and the world.