Ibis' Notes: Belle Sabreuse was reluctant to disclose information during, but my Sarah turned on the ol' Ibis charm! She begged for at least two hours on her hands and knees---just like how I got her mother to marry me! Now, unlike Belle Sabreuse, Margo agreed right away, but I wanted to put in the effort!
Belle Sabreuse can change the density of anything she touches to whatever she wishes. She claimed to be able to make her sword into a singularity, and it wasn't an empty boast. The only object denser that we've recorded is Black Swan's core. This includes clothing, which she can make into nearly impervious armor in the say way King often defends himself. Her touch can be used offensively as well, making objects brittle and easy to shatter. Her ability, however, is limited to inorganic matter. Her clothing is made of all synthetic material for this reason.
Like the Giant Slayer, she can wield her altered objects as if they were at their natural density, but, unlike the Giant Slayer, she does not have enhanced strength. Instead, her senses and reflexes are superhuman, making her a formidable foe with her sabre. Now, she---Sarah, you can stop begging! Only do that for someone you truly love!