User blog comment:Gundam Legilis/Volume 1 Weapons In Depth- Myrtenaster/@comment-10380701-20140614112631

Rapiers are like one of my favorite swords, and seeing the second revealed RWBY character wields one pretty much made me invested in RWBY.

Rapiers are pretty effective in one-on-one duels. It being made for stabbing makes it useful for precise strikes to the more... vital parts of one's body. So it's definitely weaksauce in comparison to battlefield weapons, but it is deadly in the right hands.

At least, that's what I believe.

Onto the Glyph/Dust aspects of Myrtenaster, I say this is pretty much the reason why it can be used against the Grimm. If we assume that Dust is super effective against the Grimm, then Myrtenaster is literally Weakpoint Targeter: The Weapon, as it appears to be designed specifically to deal high amounts of damage with precision.

Then Weiss fights the Giant Armor, which had no visible weakpoints.