Based off of an adorable piece of fanart by someone I follow on Tumblr. Link's outfit is also someone else's creation.
"Master?"
Receiving no answer, Link pushed open the door and crept into Demise's room. The Demon King was sound asleep on the bed, his face peaceful and relaxed. The former hero carefully climbed onto the bed, shivering slightly as a cold draft blew through the room. His clothing hardly left anything to the imagination and did even less to keep him warm. Even the many blankets he had been provided with did nothing to keep out the chill of the stone walls.
The heat radiating from Demise's hair drew the boy closer and he gently wrapped himself around his master's head, reveling in the warmth. This was perfect, he thought as sleep finally came.
~..~
Demise groaned as he came to wakefulness. As he pulled himself from the bed, for some reason his head felt heavier than usual. Perhaps it was due to the alcohol he had drunk with Ghirahim the night before?
As he looked into his mirror, the Demon King stopped and stared. Link was draped over his head, sound asleep with a smile on his face. Demise slowly lifted a hand and prodded the boy's leg. Link's eyes opened slowly but he jerked awake as he saw where he was.
"Master!"
"Good morning, Link. Would you mind explaining why you are attached to my head?"
The teen looked down, embarrassed. "I-I was cold last night."
"And so you decided to intrude on my privacy?"
"I'm sorry. I just thought…well, your hair always looks so warm!"
Demise sighed. "Child, if you were cold, why did you not simply join Ghirahim in his bed? He is always willing to have company."
"I know but he snores, Master. And I just wanted some sleep."
"Well in that case, please ask me before joining yourself to my head again."
"Yes, Master," Link said quietly, preparing to climb down.
"Where do you think you are going, hero?"
"To…start on my chores, Master."
"It is still cold in the castle. You may stay until it warms up."
"Thank you, Master!" Link replied with a grin. The former hero relaxed back against his master's head with a sigh and closed his eyes.
Demise watched his servant's reflection in the mirror and smiled to himself. This child was just full of surprises.