Senses Grendelkin

She held up a hand and said, "Wait."
I stopped in my tracks, listening. Mouse came to a halt, snuffling at the air, his ears twitching around like little radar dishes, but he gave no sign that he'd detected lurking danger.
"We're close to its lair," she murmured.
I arched an eyebrow. The tunnel looked exactly the same as it had for several moments now. "How do you know?"
"I can feel it," she said.
"You can do that?"
She started forward. "Yes. It's how I knew it was moving in the city to begin with."
I ground my teeth. "It might be nice if you considered sharing that kind of information."
"It isn't far," she said. "We might be in time. Come on."
I felt my eyebrows go up. Mouse had us both beat when it came to purely physical sensory input, and he'd given no indication of a hostile presence ahead. My own senses were attuned to all kinds of supernatural energies, and I'd kept them focused ever since we'd entered Undertown. I hadn't sensed any stirring of any kind that would indicate some kind of malevolent presence.
If knowledge is power, then it follows that ignorance is weakness. In my line of work, ignorance can get you killed. Gard hadn't said anything about any kind of mystic connection between herself and this beastie, but it was the most likely explanation for how she could sense its presence when I couldn't.
The problem with that was that those kinds of connections generally didn't flow one-way. If she could sense the grendelkin, odds were that it could sense her right back.

Side Jobs, Heorot, Page 134-135