The story begins with the sound of rain coming pouring, and the screen slowly transitions from black to the moon shining in the night sky as it rains. The sounds of metal clashing was heard, and soon a female voice was heard.

Girl: You've heard of it, haven't you? The Legend of Sparda. When I was young, my father would tell me stories about it. Long ago, in ancient times, a demon rebelled against his own kind for the sake of the human race. With his sword, he shut the portal to the demonic realm and sealed the evil entities off from our human world. But since he was a demon himself, his power was also trapped on the other side. I never believed it. I thought it was just a child's fairy tale. But I discovered that this so-called legend wasn't a myth at all. Sparda existed. How do I know?... I met the sons of Sparda. Both of them. 

(ten years ago) 

Things then changes to show a young boy with white hair and in a gray t-shit and shorts, lying on the ground. The boy's name was Drake, the son of the Dark Knight Sparda. 

He soon opens his red eyes, and notices fire in the house. He soon tries to get up, and looks up to see a woman with blonde hair running to him. Her name was Eva, the mother of Drake and wife of Sparda.

Drake: Mom, what's going on?

Eva: Come here! (leads him to a closet) You need to hide, Drake. No matter what happens, you mustn't leave! I need to find Vali. I promise I'll be back.

Drake: (teary eyed) Mom, you're scaring me.

Eva: (gently cups his face) I know this is hard. You must listen to me. Be a big boy... A man, huh? If I don't return, you must run. By yourself, alone. You must change your name. Forget your past and start a new life as someone else... A new beginning.

She then pulls back, and closes the doors. Then then runs out the room to find her second son.

Eva: Vali?! Where are you, Vali?!

Sadly, she didn't get far, as the sounds of her screams were heard, and the house starts collapsing more.

Drake then just shuts his eyes and curls up back against the wall, trying to block it all out and wish that it was just a dream.

(outside) 

At the same time, another boy with blue hair and blue eyes. His name was Vali Sparda, the twin older brother of Drake. 

He was playing near the cemetery not too far from the house. He was just practicing with a katana, when he sees the house on fire. He's about to run over, when demons appeared, surrounding him.

Vali: What?! Demons?! Why are you here?! 

They don't respond, but attack him. He tries to hold his own, but it's not enough as he gets overwhelmed. They soon back him up to a corner, and badly wound him. And if that wasn't enough, they took his katana and stabbed him with it. 

He remained lifeless against the gravestone, and the monsters were about to leave, when a blue energy starts sparking off of the boy. All the sudden...

Vali: (opens his eyes) AAAAAAHHHHHHHHHHH!!!!!!!!!!

His body exploded with a blue aura, and the monsters see that he changed into a demon. Once that's done, he rips Yamato out of his body, and at inhuman speeds, slaughters the monsters.

Once that's done, he collapses in exhaustion, and wakes up a few hours later.

Vali: (tiredly) What... happened?

His eyes then widen as he remembers what happened, and rushes to the house. But when he gets there, the house was still burning. 

He gets a glimpse, and sees two dead bodies in it. Jumping to conclusions, he collapses on his knees with tears running down his face.

Vali: Mom... (emotional) MOM!!!!!!!

Later on, he was walking away, going on his journey for more power. On the other side of the house, Drake was making his own way away with a large sword with him. Neither knew the other was alive, but this night changed them forever.

The last transition shows the moon and the rain again, but now an older Drake and Vali standing face to face against each other. 

https://youtu.be/xti_6Bzpa8A

Drake: Oh, it's you. 

Drake gave a cocky smile towards his Vali who returns it with a cold stare that lacks emotions. 

Drake: (scoffs) It's been a long time. I don't want another boring party. 

Vali: Get off my back. 

Drake: But... 

Drake then draws his Devil Arm sword, Rebellion. 

The Rebellion was handed to him by their father, Sparda.

Drake: You promised me a party, that's what I want! (charges at Vali) 

Vali: (straightens his hair) That's up to your skills. 

Drake jumps high and brings Rebellion down to do a downward slash on Vali.

Vali blocks it with his Devil Arm Kanata, Yamato. 

The brothers began their sword fight, doing strikes, blocks, and parries. 

Drake jumps and was about to slash, but Vali teleports in the air behind him and does a cartwheel with his Yamato. Drake blocked the attack with Rebellion but he was pushed back.

Drake grits his teeth as charged and yelled before he clashed blades with Vali.

Sparks were going off from their blades as the sons of Sparda jumped back. Vali got serious as he was surrounded by a blue aura around his body, the Yamato was coated as well. 

Drake smirked as he did the same. Only it was a red aura around his body as the Rebellion was also coated. 

Drake: Let's do this!

Vali: Die!

As the twin brothers unleash their own powerful attacks, they run at each other, and just as they clash, the title shows.

Kingdom Hearts 3: Fairy May Cry