Lamenterse

From Inga no Kusari wiki

Lamenterse is Mercedes's dormir. Lamenterse doesn't alter Mercedes' appearance too drastically, though it does create a metallic, jointed "armour" over her throat and neck, with two small slips continuing to her ears, protecting them from the noise as it were. It doesn't seem much, especially since it is metallic in texture, but it does protect her ears rather well from high desibel readings.

Dormir Ability

Lamenterse has two variations in it. The first and most important is a destructive, high-decibel wail: it's powerful enough to rupture eardrums, shake the brain inside one's skull, shatter glass and make cracks over the surface of harder things due to the sheer pressure coming from the wail. The other is the ability to throw out her voice, so it seems like it originates somewhere else, much like a ventriloquist, but not quite.

The range of both abilities is one mile. The wail is most destructive within the first 0,2 miles from the center: it is difficult to keep one's wits about when well over 200 decibels of sound pressure hits you head on (to compare: the human threshold of pain is roughly at 130 decibels). The damage and pressure gradually lessens the further you get from the center (that is, Mercedes) until at 0,8 - 1 miles, at the very edges of the range, the wail becomes the equivalent of a rather loud scream you'd probably want to flinch away from, but it's mostly harmless.

As for the other part, within the 1 mile radius, Mercedes can throw out her voice if she can see where the target area is. The sound, however, is always within the level of a whisper, but it is a rather good way to distract someone, or communicate. Mercedes' lips move when she's using the ability, but no sound can be heard anywhere else but the spot she chooses.