"Little brother, let's form a contract. ♡"

My demon big sister said as she led me to our private chamber. The bedroom inside was luxurious, filled with exquisite furniture that must cost a fortune. A massive bed extended across half of the room, topped with fine silk linings, fluffy blankets and dotted with throw pillows.

"Contract?"

My voice regained its functions while she took me on a tour around the palace. This bedroom was our last destination.

"Yes!" Amae placed her palms together, "In my world, contracts are the most sacred type of promises. The most common are Familiar Contract and Allegiance Contract, which I formed with my vassals. For us, it will be a Love Contract, an eternal vow stating we will be siblings beyond the end of time."

"How does it work?"

"The concept itself requires some magic knowledge so I'll save it for another day," Amae sat on the bed and beckoned me to join her. "But to fulfill the criteria, we will have to exchange fluids."

Fluids...?

My mind pictured the demon lord and I making love.

"I-I'm not sure if I am ready yet..."

Amae tilted her head with a confused look, "You're not ready for a kiss?"

I realized that my imagination was worlds apart to what she stated. As if reading my mind, a playful smirk spread across her face.

"Fufufu... Are you perhaps thinking of something naughty, little brother?~"

I averted my gaze, feeling my cheeks grow warm as she giggled playfully.

"The initial preparations are complete, ready?"

I'm afraid...

I paused for a moment and muttered softly.

"What if I am not good enough...?"

Memories of my past life shot through my mind.

I'm afraid... I will let you down.

I don't want you to hate me...

Amae held my hand and stared at me with a gentle expression.

"Everyone has things they are not good at, do they not? Even a demon lord like me who had lived over five hundred years have things I am bad with."

My big sister smiled tenderly and patted my head.

"And I know you are already doing your best. Even if you fail and feel like you are not good enough, I'll accept all your flaws. And one day, I hope you realize that you are good enough."

In an assertive yet loving voice that I always remember.

"Failure or not, I will always love you. ♡"

My heart trembled at those precious words. This was the first time that someone accepted me for who I was.

"Let's form the contract."

In a swift movement, a pair of magnificent black feather wings sprouted from her waist and wrapped tenderly around me, enclosing me into her embrace.

A gigantic dome-shaped magic circle materialized around us. It shone a soft red, and translucent diagrams of various characters and symbols appeared. Those shapes changed ceaselessly, differing from second to second.

I paid no attention and focused solely on my big sister, finding my reflection in her hypnotizing golden eyes. Although they seemed bestial, something about her gaze made this moment so mystical and breathtaking.

Time seemed to slow down.

Only me and her in this ineffable moment.

Nothing else mattered.

Our fingers intertwined as Amae closed her eyes and pursed her lips. She leaned towards me, stopping inches away from my face.

Now, it was my turn.

You loved me when I couldn't love myself.

Our lips pressed together.

Thank you.

And gently, her tongue greeted my outer lips as if it was asking permission to enter. I parted my mouth and welcomed her inside.

Immediately, pleasure shot through my mind as she entered. I felt our tongues grazing each other repeatedly, exchanging saliva and fluids.

What is this feeling...?

Static sensations. Although my eyes were closed, they were rolling back in pure bliss.

It feels so good...

My strength drained away as she continued to intertwine my tongue. I was in a state of heaven. My mind went blank and my arms went limp. As intense sensation washed over me, I could only silently beg for more.

I'm melting...

♦ ♦ ♦

"原來你是我最想留住的幸運~ ♫ 原來我們和愛情曾經靠得那麼近~ ♪"

I yawned groggily, hearing soft humming to a beautiful song with lyrics I never heard of.

"Ara~ You're awake ♡"

I opened my eyes and saw an elegant goddess, her eyes glazed over me with affection and care. I realized that she had cradled me tightly in the midst of her wings while I was asleep. Resting in her fluffy embrace, I felt like I was lying on the world's softest bed. There was only one word to describe this feeling — it was heaven.

"What happened?"

"Sorry, little brother." Her cheeks gradually became a faint rosy pink as she said sheepishly. "When demons become too aroused and reach a certain threshold, we release oxytocin into our saliva. And while we were kissing, too much oxytocin entered your body during the contract."

Oxytocin. Also known as the love hormone, often secreted when lovers snuggle, cuddle or have sex.

Does that mean parts of her are inside of me right now?

"But the Love Contract is complete," Amae beamed brightly as she shifted her body back and forth. "Now that we are official, I want to hear you say it."

"Say what?"

"I want to hear you call me big sister."

As if she was an eager puppy, she gazed at me with a pair of innocent eyes and waited patiently.

"B-big sister."

"Yessss~," Amae exclaimed as her eyes sparkled in merriment. "P-Please say it again!"

"Nooo... Only once per day," I stuck out my tongue.

As Amae sulked adorably, I laughed and dived into her warm embrace, feeling reunited with the partner I vowed to spend the rest of my life with.

One day I'll muster the courage and say it, big sister...

...that I really, really love you.