With a careful touch of his brush, Shin painted the last line of his talisman. When the ink didn't ruin his third attempt, he let out a sigh of relief, put the brush down, and flexed his tired fingers.
Despite his exhaustion, he was happy with his work.
After the last encounter with the toilet slime, Shin spent the rest of the day reading stolen magic books. All with one purpose.
"Tetsu," he said, standing up from his desk and picking up the talismans. Four of them made a formation he was about to create.
"Yes, my friend?" she asked, appearing from his back. Her hands fell on Shin's shoulders, massaging slightly. "Your muscles are so tense after all that writing… I can feel how uncomfortable you are. If we merge again, we'd be able to fix that…"
Shin shook her hands off. "It will pass on its own. I just need you to give me the power to activate this formation."
"Oh, this." Tetsu stepped fully out of Shin and looked down at the talismans with tightly pursed lips. "Are you so sure, partner? Don't you trust my ability to protect you? Why do you need to make any other demons? You have me! I'm better than whatever that creature is supposed to be!"
The more she spoke, the more agitated she became. Shin felt the jealousy, plain as day, welling in her.
Tetsu stared at him expectantly. She was panting, and her chest went up and down, attracting Shin's eye. He blinked and looked at Tetsu's lips instead.
Too bad her eyes were covered by that helmet she always wore. Tetsu's lips were just as soft and inviting to touch.
"You can't be serious," Shin said, pulling his mind out of the gutter. "Tetsu, this is just a spell. Yes, technically, it's a demon, but it's designed with a single purpose. It will barely have any sentience at all! It will be like an insect."
"So what? Insects… animals… even plants. They all have something fascinating in them." Tetsu leaned forward, and her tone became more serious. "My friend… I know you don't care for me in the same way I care for you. But I know you care more than you did when we first met. Back then, I was only a means to an end, wasn't I?"
Caught off-guard by the sudden question, Shin didn't know what to say.
Tetsu smiled, showing a glimpse of sharp teeth.
"That's alright, my friend. But if you can start caring for me, why can't you start caring even for that insect?" she pointed at the four talismans on the table. "You can. You can, and I wouldn't be able to bear this. No, no, I would never. To feel that emotion in your soul and know it's not directed at me?"
Her smile widened into a dangerous grin, drawing even closer to Shin.
"But that would never happen. Right, my friend? You would never… replace me this way. Right? I'm just scaring myself."
She laughed softly. Tetsu's face was so close to Shin that he could feel her breath on his.
Despite his exasperation and a hint of fear, Shin blushed. It was frustrating.
"Tetsu, you are making no sense. How can I EVER replace you? We are Contracted! We can't separate without tearing out a piece of our souls, and this might even kill us. Why would I ever do that?"
"I don't know." Tetsu tilted her head to the side. "Or I don't remember? There's still so much I don't know about humans, but most of the others we've met didn't like their Contracted demons. Maybe one day you would stop liking me, too. Maybe this is the day?"
"No!" Shin grit his teeth and put his hands on Tetsu's shoulders. If they got any closer, they would kiss now. "Tetsu, I believe in you. You proved your loyalty and your worth, and I trust in them. Don't you trust in me?"
And to Shin's great relief, the aggressive tactics worked. Tetsu moved back a little, her volatile emotions turning to something else, less dangerous.
"O-of course, but… But…"
"We have a lot of work to do to defeat everyone who wants our heads, Tetsu. Why should we do this all ourselves? That's what servants and spells are for. To make life easier for us both. Don't let your emotions stand in our way, Tetsu."
Shin took a step back and watched as Tetsu stood straighter.
"I get it, boss, and I'm so sorry! I… I got really scared, but you always know how to calm me down again!" Tetsu beamed at him. "Now I will work even harder to help you! To make spells, too."
Shin let out a tired breath, picked up the talismans and went towards the exit. "That's right, Tetsu. Let's go outside, then."
There, Shin placed the paper talismans on each of the four corners of the house. As he did this, he explained things to Tetsu, who returned to his body.
'The formation has two Verses. If I were just a human, I'd need to make a human sacrifice or two to fuel its creation, but with you, Tetsu, it will be much easier. Active, the formation will prevent any unbidden guests from entering my house, and even kill the weaker ones. Including the toilet slime.'
'Oh! So that thing won't interrupt your bath time again. I hope it tries to enter again and burns.'
'Yes. And if this formation works as it should, I will work on making more complex ones. Things like shikigami, or golems. Something that will go on its own, track the other transmigrators and deliver them to us. It will be much faster than searching for them on our own, and we don't have unlimited time. The Fourth God might be killing them as we speak.'
Shin placed the last talisman and placed his hand on it. He concentrated, focusing on the mystic energy within himself.
'Alright, Tetsu. Like you gave me the strength of your body before… I need the power of your soul. The magic that all demons have.'
She smiled wordlessly at him, and magic poured out of her, through Shin's fingers, and into the formation.
Their first spell, their first demon, was coming to life.