My  own puppy is the perfect model for this, considering our mc was based of him. Fumu, his antics are materials for this novel.

-----------------

As my body grew, pain started to appear as the collar around my neck squeezed it tightly, causing whispers to come from my throat as I wheezed for air, attracting Nathan's attention.

With careless fingers, he undid the binding and at that moment, my formed changed.

With a red face, he quickly dropped my onto the ground.

And without hesitation, I ran on four limbs.

Fumu, goodbye to this life! Ufufufufufu!

Without thinking, I dashed as fast as my limbs could go, the uneven length of my arms and legs causing some difficulty, but even so, I was making rapid progress towards the exit.

Almost there! 

I'm a step away! 

Closing my eyes and bending my head downwards, I increased my speed to  the maximum and charged forwards.

With one hand crossing the gate, I felt immeasurable pride as the sides of my mouth moved upwards, something I couldn't do before changing, but now, I instinctively did it.

Taking a leap forwards, I was out of this hell. 

Fufufufufufufufufufufu. Go buy another pet! You don't need me!

As I was relishing in my freedom, a strong pull at my tail caused my chin to hit the floor, followed by my belly.

"Oi, where do you think you're going?" An all too familiar voice called out from behind me.

Turning around slowly with abated breathing, I saw Naomi, her devilishly beautiful face, a furrowed brow tainting it.

"I didn't think it would happen so quickly......we'll have to make a new collar now, don't we?" She muttered with a tilted head, her impossibly strong grip on my tail unrelenting.

......I was so close...!

This is......unfair!

With tears collecting in my eyes, I could only wallow in how unfair everything was.

Rubbing my eyes with my arms, I looked up at Nathan who towered above me, who was seated on the ground.

"Does it hurt......anywhere?" He asked looking away.

Sniffling, I looked at the ground again, my hands in front of me.

It looked just like the demons' I had five fingers and long claws, my skin was pale and had silver pulsating streaks of lights running across it. 

Tumbling from my shoulders were thick long locks of silver hair and turning back, my tail was the same. 

Letting go of my tail, Naomi stood up and ordered, "Stand up." 

Looking up at her, I could only bite back the tears and follow her commands, it wasn't like I could do anything else.

And before I knew it, a towel was thrown around me by Nathan, who finally looked my way, though red still dyed his cheeks.

"She's about five years old?" Naomi muttered, looking up and down.

"Does it matter? Let's return to the building first." Nathan spoke as he grabbed my hand.

Looking around, I noticed how the surrounding the people around glanced at me with pity as I slowly returned to their home.

The entire building belonged to them, with two floors and beautiful decorations, it was fitting for the royalty.

The moment we entered, brother appeared within seconds, the ominous sound of his claws clicking against the floor was heard as he tumbled into our sight.

Sniffing around, he finally recognised me with a confused expression.

Fumu, I just noticed this but in this form......I'm taller than brother!

This time, I snorted in his face as my tails swayed around in pride, my head tilting upwards as a smirk appeared on my face.

Fumu, the tables have turned.

Noticing how I had copied his condescending actions, whimpers came from his throat as he glanced at his own owner, pawing at his feet.

"What's there to be jealous about? You'll grow too." He spoke, rubbing his head.

"Sister," he started, turning around to look at Naomi who stood behind him, "You'll need to get some clothes for her."

"I know that, I'll prepare them by tomorrow, the day's still young."

Suddenly turning back to me, Nathan asked with worry, "You want to get some rest?" 

Nodding weakly, he picked up my hand as he brought me upstairs where Naomi's bedroom was and tucked me into bed.

"Get some rest, we have school tomorrow." 

Leaving the room, I was left to slowly fall asleep. 

Someway along the line, night came and Naomi came in, with the click of unlocking the door, she slid into the excessively large bed.

This story is posted elsewhere by the author. Help them out by reading the authentic version.

And in the next morning, I woke up by myself, next to me a bundle of clothes, or what I prefer   to call edibles.

"Umu, thank you for the food." I muttered as I dug in, my canines still here and my claws still effective.

As I was halfway through the pile, a knock came from the door as the familiar click was heard before it opened, allowing a servant to come to my sight.

"What are you doing!" She exclaimed upon noticing my actions, with quick steps, she ran to the bed and attempted to snatch the clothing in my mouth away.

However, with a growl, I dashed off the bed, barely able to crawl under the bed with my larger form, hiding in the middle.

"Come out!" She shouted, her hands reaching in to grab me witj her body lying on the groind, yet she failed miserably.

Fufufufu, I win, you evil woman!

Only after a long time did she give up, standing up, she dusted her dress, she left with the click of the lock.

Noticing how the threat was gone, I crawled out and perched myself onto the fluffy bed, this was my first time sleeping on something so comfortable. 

In the past I was too small to jump onto the bed and usually slept on the first floor.

At this point, I'm just like a king aren't I? This is a promotion! A promotion! 

As I basked in my glory, the click was heard again as the twins appeared.

"You!" Naomi shouted, pouncing onto the bed as she grabbed the shirt I held in my mouth, whacking my head.

"Ow!" Grabbing my head, I let go of the cloth and tumbled backwards, "That hurts you stupid stupid stupid demon!" 

"You can talk?!" She asked with wide eyes.

"Why can't I? I hate you! You stupid demon! You're always reading in classes and passing your studies so nicely! What kind of a child are you! You weirdo!" As I started, my mouth continued rambling without rest.

"Wha- you stupid dog!"

"You're the dumb one! If you have a problem then throw me away! I don't want to stay with you!" 

"You!" She crawled over, trying to grab my arm, yet I darted fast enough off the bed.

As the two of us bickered, snickering was suddenly heard.

"What's there to laugh about?!" "Why are you laughing?!"

Hearing the two of our shouts, he quickly regained composure as he feigned innocence, "I wasn't laughing." Yet finishing his sentence, he snickered yet again.

"You! Fight me!" I shouted, pouncing at him, pushing him to the ground as I sat on his stomach, my paws scratching at his impossibly tough skin.

As I continued to do so, suddenly a black mass of fur barrelled my way, pushing me off and sitting on me.

Fumu, I won't forget this betrayal, brother.

-----------------------

After that, we spend a long long time dressing me with all my resistance, and collaring me, we left for school.

At first there were a lot of glances, but at lunch, perhaps after all the interest had died down, I was left eating on the table with the twins while brother laid under the table.

Fumu, is this a promotion? Fufufufu. 

I was given a large abundance of meat, and meat, and meat, and a crystal.

This time, it was thankfully green instead of red, I'll take it happily.

Halfway through the eating, the familiar prince I met last time who had came to this table, came again with brother #2 behind him.

Noticing our sibling, Acer darted forwards to greet him with a happy wagging tail, while Naomi held my shoulder. 

"Reiman, is there any problem?" Nathan said lazily as he played with his food with a fork.

"No, I'm just curious about that......beast man, we all thought it would die." He shrugged, staring at me.

Againn, with this cruel way of looking at my life...

Baring my fangs, I growled at him with meat still hanging from my teeth.

"How cute." Nathan commented as he rubbed my head, "Then it's a good thing she did not, no?"

"Certainly." he muttered, "Perhaps I should do the same?"

"And how does that concern us?"

"Don't be so cruel, I'm just here to talk to Naomi, not you."

"I-im flattered, but please let me and brother and eat in peace." She stuttered pretentiously. 

Snorting I thought mentally, "How fake." Yet it somehow came from my mouth, attracting their glances and her glare.

Covering my mouth, my ears flattened as I looked down.

This talking thing, how troublesome.