You were wrapped up in a blanket in a small box and crying. Your mother died soon after giving birth to you and your father felt that he couldn't take care of you after her death. He regretfully left you in an alleyway and never came back. There was a note on your box saying,
" To whoever finds this.
Please take care of this baby. He has no mother and I feel that I am in no way able to care for him. Please take good care of him for me."

A cat faunus heard your cries and headed to find you in the box. She read the note and gently lifted you into her arms. Your white baryonyx tail twitched as you cried. The woman decided to take you into her family and she held you close and as gently as possible as she carried you to her house. She couldn't believe that anyone would abandon their child. But she vowed to take good care of you. She also felt that her daughter would be happy to have a little brother. Soon she reached her house and headed inside. You looked starved, so she grabbed a milk bottle and began feeding you. You eventually calmed down and fell asleep in her arms. She stroked your tail gently and kissed your forehead. You woke up an hour later to find her looking at you.

"Hello there little one" , she said as she stroked your white hair gently. You cooed and reached up to her. "According to the note I found , your name is Rudy. My name is Kali. Blake will love meeting her new little brother" , she smiled as she carried you to the living room to find Blake. You saw a small girl with black hair and cat ears the same as Kali playing with some toys. She looked at you.
"Mommy who's this?", she asked
looking at you.
"Blake , this is your new little brother Rudy", Kali said to her. Blake gently touched your hand and you instinctively grabbed it. She giggled. She always wanted a little brother.

Timeskip a few years later

You sat with your big sister and your white baryonyx tail swished happily as she gently scratched you under your chin. It was something you always loved. You were now 15 and your sister was going to be going to Beacon in a couple of weeks. You hugged her tightly.
"I'll miss you Blake", you said to her.
She gently stroked your tail and kissed your cheek.
"I'll miss you to little brother. Be sure to visit if you can", she smiled at you "I will" you said to her. Soon she had to leave. You waved to her as she embarked on the transport.