It was another foolish human who had dared to make an advance on Tanjiro as they stood waiting for the train to the outskirts of the country. Of course it had to be. No demon would be ignorant of Muzan’s presence and they certainly wouldn’t summon the gall to touch his pet’s earrings without a word of permission. That was at the very least. The boy looked slightly older than Tanjiro but he had a hand interlocked in his and was showering him with compliments that didn’t leave much room for interpretation.
“Kamado.” he said, folding the newspaper he was witnessing the obscene display behind and standing up to his full height. Today he donned his formal attire with an elegant pattern embroidered in a red that matched his piercing gaze, “Let’s go for a walk.”
“Whoa! Is this your dad?” the kid asked Tanjiro, clearly intimidated. Muzan would not, however, be satisfied until the fool had taken his filthy hands off of his boy. Tanjiro seemed to have realised the danger the other had placed himself in and tried to disentangle his arm without neglecting to be polite.
“Ah, not really.” he said, laughing nervously, “Why don’t you go back to your own parents now. I’ll catch up with you later?”
That was more like it. Now, if only the kid could take a hint. The frown on Muzan’s face deepened.
“Why are you listening to everything this old man says? It’s not like he owns you.”
What a fool. What an absolute fool . It hadn’t been longer than a second before Muzan saw a line of blood spill on the stone platform tiles. Tanjiro was watching in abject shock as Muzan dug his nails into the boy’s neck mercilessly. Like he was witnessing the slaughter of a delicate bird.
“If you leave now,” he whispered, tightening the grip, nails digging in to squeeze the life of their cut, “I won’t kill you.”
A choke, a desperate nod, and then release. He watched Tanjiro’s eyes follow the scrambling figure disappearing into the crowd and felt a twist in his gut at his expression of fear.
“Look at me Tanjiro.” Muzan said, grasping his pet’s chin in his hands and turning it to face his own, “You do belong to me. I will protect you from any liar who tells you otherwise.”
Tanjiro grimaced at his tight grip and Muzan immediately loosened it. He lost control of his strength when he felt possessive. It was a little concerning. The fact that Tanjiro had brought that side of him out on more than one occasion.
“Yes, Lord Muzan.” he said, the warmth of his cheek meeting the inside of the demon’s palm when Taniro leant into his touch. He was too good for him, this boy. He didn’t deserve it. But then again he didn’t deserve to have the weight of the sun restrict him due to its lethality either.
“Good. You can sleep on my shoulder for this ride as a reward.”
Tanjiro’s ears turned visibly red. Only Muzan was allowed to make him feel this way. Only him. Ever since they had set across on this journey to find the final ingredient required to turn Nezuko back into a human, Tanjiro had accidentally fallen asleep on Muzan’s side during the longer train rides. It was true. Tanjiro despised him. How could he not? The decision to offer himself as Muzan’s pet in exchange for his family’s humanity was a begrudging one. All of this made the fact that Tanjiro took some unintentional pleasure in falling asleep against his shoulder to be all the more cruelly conflicting.
“Don’t bother trying to fight it.” Muzan said, entangling his fingers in Tanjirou’s hair, sifting through the soft strands, “I know you’re enjoying yourself.”
The boy let out a sharp breath and closed his eyes to the touch. He always melted for Muzan. Just for him. As soon as they reached their destination he was going to pin the other to a wall and mark that neck till his work was all anybody could see. He had already dressed Tanjiro in a yukata, collar bones visible to the naked eye. They would show. Nobody would dare to touch him after that. Not unless they wanted to lose life or limb.
“Yes, Lord Muzan.” he said, trying to avoid whimpering the demon’s name. The disgust in Tanjiro’s half lidded, half lost gaze was acidic. If it were a poison it would be potent enough to burn through Muzan’s organs. His mind went back to the dripping claw marks he had left on the unfortunate soul earlier. The look on Tanjiro’s face made Muzan feel as though he may as well have constricted himself.
The sound of the train’s engine was deafening. He shook his thoughts and put a hand on the small of Tanjiro’s back, guiding him past the crowd and the station master to their car.
“Do we have this to ourselves?” Tanjiro asked, closing the door to the compartment behind them when they had reached.
“As always.” he answered, watching as Tanjiro seated himself and gazed up at Muzan bitterly yet expectantly. He really was a sight to behold when he wanted something. Especially when Muzan was the only one who could offer it. He leant down and kissed the boy, nothing more than a swift nip at his bottom lip.
“Who do you belong to?” he asked staying still after the bite, feeling Tanjiro’s breathing against his skin and the flutter of his eyelashes against his cheek. Tanjiro growled and bit back with fervor making Muzan smirk.
“You. To you Lord Muzan.”
Good boy. He didn’t have to say it out loud. Muzan sat down by the other’s side and watched him lay his weary head, sure to be warring with itself, on his shoulder. It was not long until the lull of the moving train over the tracks swayed him to sleep and the poison Muzan felt running through his veins made him wonder if he was suffering a slow, waking death.