More:
The twins have occupied a place in area folklore for at least two hundred years, though they aren't especially aware of their notoriety. They have been accused of carrying away farm animals (possibly true), damaging tools and equipment (also possible), souring milk and spoiling crops in the ground (if true, they're unaware they're capable of it), spiriting away children (not really interested), and punishing the wicked (also uninterested). For the most part, they stay in the forest, pulling pranks on travelers or anyone who tries to find them. Notch, the more malicious of the two, would sometimes like to go farther, but Nudge keeps her in check. Local legend has it they used to be human, but they wouldn't know.

Sample:
"Nudge, I saw one!" Her sister's shape bloomed from the tree's shadow and skittered lithely up its trunk, finally appearing in front of her with mouth gaped in a wide grin.

"Where?"

"On one of the hunting paths. He hasn't been here before. He's not trying to sneak."

"Does he have food?" She slipped forward, sniffing delicately at Notch.

Truth, for once. She smelled the distinct tang of human, though the scent was muddled with something she couldn't identify.

"Maybe he can be food," rumbled Notch, craning her head, presumably in the direction of their mark.

"No." She sprang to the ground. "They won't come back if we kill them, will they? Besides, they don't taste good."

There hadn't been as many humans in their woods in recent years, and the farmsteads nearest the tree line had fallen into disrepair. No one left them milk or baby goats anymore, and the animals in the forest had grown canny to their hunting.

Her sister made a disgruntled noise. "But --"

"Nooooo." She waited until her sister had joined her, then nuzzled up under her chin affectionately. "They're no fun after they die."

Notch nipped delicately at her ear and sighed. "All right, he won't be food."

"Show me where he is."

He was nearer than she'd suggested. Nudge caught his scent after only a few feet of travel, and she felt herself quiver at the prospect of a game after so long.

"Should we try the usual?" Her sister arched into the silhouette of a deer, prancing briefly along the path before sinking back into shadow.

"If he's really hunting, it might be best ..."

"Hunter or prey?"

"You always get to be hunter, Notch."

"Fine." She slithered close and nuzzled into her sister, nipping her again. "You can be hunter this time."

Nudge trilled a laugh, and they broke away, Notch to the fore as a frightened doe and she to the back as whatever shape was most convenient.

She blinked as the human came into view. He wore clothes she'd never seen and didn't carry a bow. Instead, a contraption that smelled of metal and fire hung loosely in one hand, teasing her nose and almost making her sneeze. She felt a spark of unease, but Notch had already given the signal, ready to spring.

She coiled into a shadow, letting out another soft trill.

The hunter stiffened, turning sharply toward the sound, and that was when Notch leapt into the open, a dash of shadow in the pale moonlight. He spun again and lifted the contraption, and that was Nudge's cue to spring.

She was in the air when a booming crack tore the air, accompanied by the scent of smoke and followed by her sister's scream.

"Notch!" She collided with the hunter, sent him crashing to the ground, but she was beyond him in a bound and at her sister's side.

"He hurt me!" she wailed. "It was too fast --"

The scent of blood burned her nose. She shot a panicked glare over her shoulder, but the hunter was still stumbling to his feet. Rage rattled her frame, but Notch whimpered again, calling her attention back.

She gathered her sister up and fled to the darkest patch of forest she could remember.