Twins of light and dark

Late Night

*DISCLAIMER! Pic edited by me. Please credit me if you want to use it. It's a little sketchy since I haven't made digital art for a few years now :)*

The night air was warm and silent, a soft breeze rustled through the trees comfortingly as the moon shone in the sky on this summer's night.
A shadowy figure walked through the forest on the path towards the Mystery Shack, the cape it was wearing barely scraped the forest floor. When the shadow came into the light of the full moon, it seemed to be a male, about 12 years of age, with black hair and pale skin which was icy cold to the touch. He had a strange birthmark in the shape of the Big Dipper which he hid behind a black fringe; that wasn't the most unusual thing in his appearance.
He had slightly pointed ears and sharp nails, bright red eyes with violet, sleepless shadows around them and a pair of fangs in place of a human's canines.
The boy also wore formal clothing, consisting of a maroon coloured tie, a white shirt, black jeans, maroon coloured socks and black ankle boots as well as a black and red pine tree hat in addition to his black cape.
This was Dipper Pines.

He silently entered the shack, closing the door behind him before he ascended the stairs to the attic room, creaking open the door.
There was his twin sister, Mabel Pines, fast asleep in her bed.
Dipper wore a small, fanged smile, slipping into the room like a ghost in order not to wake Mabel, taking off his cape and folding it up, placing it at the foot of the bed.
"D-Dipper?" Mabel's sleepy voice murmured. Dipper froze, his back to his sister.
"What time do you call this? where were you?" she asked. Her skin was sparkling, glittering even, in the moonlight.
"I.....I was out for a walk, Mabel" Dipper replied, feeling a tug of guilt in his heart at the lie.
"Yeah, but you came in so late. Come to think of it, you did the same thing last night.....and the night before that....and before that" Mabel counted.
Dipper chuckled softly.
"Not funny, bro-bro! it's hard to stay up late waiting for ya!"
"Sorry but I like going outside at night. Besides, I can't really go out in the day" Dipper said, the last part of the sentence barely audible as he stared at the wall.
"What do you mean?" Mabel asked, confused at the last bit of the sentence.
Dipper sighed.
"Alright. I'm going to show you something I haven't shown anyone before. Just.....don't freak out, okay?" Dipper requested, still not turning around.
"Cross my heart, Dipping-dots!" Mabel said cheerily, which made Dipper laugh again.
"Okay....ready?"
"Yup."
Dipper took a deep breath before turning around, his red eyes glinting in the moon's glow. He then gave Mabel a smile, showing his sharp white fangs.
Mabel stared, her eyes wide.