It's the nature of the creature, I think.

"He was born" Even eyeless, she knew the dark nature of the creature to which she had given birth.

So this was the real nature of the creature!

It seemed to him that such needlessly formal sentence structure might easily betray the robotic nature of the creature.

The slender physique and pointed ears left no doubt in his mind as to the nature of the creature.

Only Allanon seemed fully to appreciate the nature of the creature.

Had she known the nature of the creature lurking there half its menace would have vanished.

We were slow to comprehend the nature of the creature.

But Taggi, outraged at the nature of the creature he had attacked, squalled and retreated.

Indeed, it has to do with fathoming the very nature of the creature.