Delirium Worldbuilding: Waking to Nightmare

He stared at his reflection in the darkness and unconsciously muttered a curse. The fright faded away, leaving a small smile of amusement in its place. He even scared himself sometimes.

There was a small rustling to his right, where a pink bed and several stuffed creatures were, all various shades of rose. The small girl that was sleeping there had turned over, her face pale in the light of a princess night light. Her eyes flickered behind her eyelids with nightmares, a small moan escaping. He stilled and watched, barely breathing. If she woke, it might ruin everything. Why did his body refuse to move, to simply slip away and close the door?

The girl gasped, blue eyes fluttering open. He could hear her breath coming in short, panicked bursts, slowing down as the nightmare faded from reality. It was several moments before she spotted him there in the doorway, a curious look written on his mask. She sat up, clutching her blankets, too frightened to scream.

Breaking from his indecision, he stepped up to the foot of her bed and simply stared at her as she cowered. "...How old are you?"

Her eyes widened. "S-Six...Please go away..."

"Why...Do I frighten you?"

She nodded.

He sighed. "I always do. But that's simply me."

The girl seemed encouraged by his lack of further movement, sitting up a little straighter and fiddling with her nightclothes. "I-I'm Emma..."

"I saw."

"What..." She paused to swallow. "W-what do you want?"

"From you? Nothing. I was curious..." He paused. "I didn't know I had a sister."

"S-sister?" The girl clutched at her hair.

He shifted his weight slightly and crossed his arms. "Yes. You," he said, cocking his head a little.

She shrank under his gaze, eyes darting around in a refusal to meet his. "W-What's your name?"
He didn't answer for a moment. "I don't have one."

Emma looked at him. He wondered just what she saw. He was going to have to do something about this.

He shifted again and gazed out the window. He heard the girl slowly pick up a stuffed bunny and hug it to herself, hiding most of her face except for the vivid blue eyes peering up at him with a mixture of fright and curiosity. She couldn't see it, but his eyes were the same icy color, the only part of his face that resembled something human. He reached up and touched the porcelain smile he wore.

"Why are you wearing that?"

"Hmm?"

"That mask. Why's it look that way?"

He sighed deeply and walked around the bed to move closer to her. She backed away, nearly falling off. He partially climbed up in order for their faces to be inches away. She started trembling again, a few tears escaping.

"...Do you really want to know?" he whispered.

She shook her head frantically.

He smiled.  "Good girl."  Slithering off the bed, he unplugged the night light, plunging them into shadow. "Now. Go to bed."

He didn't move for a moment and listened to her whimper. Then he put the plastic princess on the carpet and closed the door behind him with a soft click, casually resuming his business as he went deeper into the still mansion.