Which could make sense. I mean, she's one of the last Umbra witches, which means she's one of those who remains in darkness, one of the few dark beings left on earth, thus a 'shadow'. If the 'shadow' is destroyed, it is no longer cast and is bathed in light or sunken into darkness, a greater shadow.
That's how I figure it.
"Then next time, I'll take a pose when I'm in great condition. OROBAS!!!" - Junpei Iori Parody, Persona 3, Tartarus Theatre.