https://www.youtube.com/watch?v=pRKPqQyIzA8

Scarlet *shocked*: W-What did y-you s-said...?!

Midnight: Is the truth, Scarlet. Saori is our daughter.

Scarlet: H-How can this b-be... possible...?

Breeze: When Saori and Kazuya had 8 years old, Saori started to discover and unleash her devil energy. She loved the moments that Midnight and she readed some poetry and story books, but she doesn't liked the moments that Kazuya bothered her. She wanted to read alone and in peace or with her dad, but I guess she didn't love her brother.

Scarlet: What do you mean with that?

Breeze: ... Saori is a devil prodigy. With 8 years, she turned into a great warrior, but Kazuya couldn't follow her steps, staying behind her. He never could beat his sister.

Scarlet: Why do you 2 hided Azure and me this secret?

Midnight: She's very dangerous, and more now that she have Yamato.

Scarlet: What we'll gonna do now?

Breeze: ... Let's pray that she leaves Kazuya alive.

*In Temen Ni Gru highest point*

Saori: You're not worthy as my opponent, little brother! *Judgement Cut*

Kazuya *avoids the attack*: Yeah, maybe I'm not a worthy opponent, but you can't beat our father! *takes his Red Queen and uses Exceed*

*The twin devils crossed their blades, but Kazuya losed the control of his blade. Saori tried to cut him some times, but Kazuya could avoid all the cuts*

Kazuya: Come on! *shoots a charged shot of his Blue Rose*

Saori: Hmpf *deflects the charged shot with Yamato*

Kazuya: Ha, you're wide open! Shadow Clones Jutsu! *20 shadow clones appeared*

*All Kazu's clones went to his sister*

Saori: ... It's useless *she created a giant vortex, trapping all Kazu's clones*

Kazuya *trying to escape*: I-I CAN'T... M-MOVE...!

Saori: My power shall be absolute! *Judgement Cut End*

https://www.youtube.com/watch?v=vNMqiYl8inw

*The white-blonde haired devil woman, started to cut the air, and when she covered Yamato on his sword holdster, all Kazu's clones dissapeared and died. The real Kazuya was on the floor, with 2 giant cuts on the chest*

Kazuya: *coughs and loses blood*

Saori: What's the matter? Your big sister is very strong for you? Hmpf, you're only making me lose my precious time. Give me the amulet, and I'll let you escape.

Kazuya *stoods up hardly*: D-Don't m-mock me...! This necklace... is precious for me... and I won't l-let you... h-have it-! *coughs blood*

Saori: Hmpf, pathetic *summons rose swords*.

Arkham: Wait, my lady!

Saori: ... Arkham. What do you want?

Arkham: Let him live. He would be a good puppet training, and the first person that will feel the fearless power of the mighty Speedster of Darkness, Saori Blade.

Saori: ... Okay *goes to Kazuya and steals his necklace*

Kazuya: W-Wait...! *tries to stop her*

*In a horrible and bloody act, Saori stabs his own brother on the chest*

Kazuya: GWAAAAAAAH! *loses a lot of blood*

Saori: Foolishness, Kazuya... foolishness. Might controls everything, and without strength you cannot protect anything... let alone yourself *takes off Yamato of Kazu's chest*

*Kazuya falls on the floor*

Arkham: You got it?

Saori: Yes! Now the world will be on my feets! Nobody will stop me *walks to Temen Ni Gru's edge*

Arkham: ...

*Suddenly, a blue energy started to flow on Kazuya's body*

Saori: ... *stares Kazu*

Kazuya *heals his wounds*: ... You got... that right. I'm not a... worthy opponent for you... Onee-san. Mom and Dad always gived you more attention. I'm just your useless shadow. But now... I have a family to protect. They gived me their... hope and... pride. I... I...!

Saori *thinking*: His energy is skyrocketing...

Kazuya: I WON'T LET YOU DESTROY MY WORLD! *transforms into Sin Devil Trigger by one instant, and then, he faints*

Saori: ... I wanna see you try it.

*On Temen Ni Gru's base level*

Midnight: ... Huh?

Scarlet: ... What's wrong, bro?

Midnight *shocked*: ... No... it can't be...

Breeze: D-Don't tell me... that...

Midnight *shocked*: S-She defeated him... but he's still alive. His energy it's almost done.

Breeze *crying*: ...

Scarlet: No... so that girl... it's more stronger than we thought...

Midnight: You don't know what can do Saori to you. She's a true monster.

Breeze *crying and thinking*: I can't believe it... Saori, what we made it to you? Have Midnight and I educated you so badly?

Midnight: ... That's enough. I won't let Saori kills her own brother *bites his thumbs, loses a little of blood, and starts to make hands poses*

Scarlet: What you'll gonna do now?

Midnight: Summoning Jutsu! *Shadow (the Black Panther) and Griffon (the Electrical blue bird) appeared*

Griffon: Hey, Midnight! It's been so long time that we don't see our faces! *stands on Midnight's arm*

Midnight: Well, I guess you know what's happening now.

Griffon: Let me guess, your demonic daughter and her cute little brother are fighting each other, isn't it?

Midnight: Yup. We must stop Saori, before's too late.

Griffon: Okay... Do you have any idea?

Midnight: We should separate. Breeze, take the stairs and go up. Scarlet, take the central door. I'll go with Griffon. Breeze, I'll give you Shadow.

Breeze: Why?

Midnight: We'll gonna fight against our own daughter, and you don't have your fan with you. You should get a partner. But remember, Shadow can't kill the enemies. You must do it.

Breeze: Got it, dear.

Midnight: Okay. Let's disperse!

*On the Lair of Judgement (Temen Ni Gru's room)*

Arkham: This is the door, my lady.

Saori: Perfect.

Arkham: Temen Ni Gru will finally regain it's full function, and lead us into the demon world... the world where Sparda's power has been sealed.

Saori: ...

Arkham: And the one who will lift the incarnation, it's you... his own granddaughter.

*Lair of Judgement's door starts to open*

Arkham: ... Go ahead. The ultimate power is waiting you, my lady.

Saori: ... *walks and when she's gonna pass the door, she stops*

Arkham: ... What's wrong?

Saori: Why do you stopped me to kill my brother?

Arkham: ... What are you talking about?

Saori: I was going to knockout him, but you stopped me. Does some pesky fatherly worry, got inside you?

Arkham: That's not of your busin- *Saori stabs him with Yamato*

Saori: ... To further your studies on the black arts, you sacrificed your woman and daughter... to became a devil as well.

Arkham: *loses blood and he throws the book on the floor*

Saori: Knowing this, I've thought that you would be more useful for me... but I was wrong. You're so pathetic, Arkham.

Arkham: What about you? You're an incomplete being as well.

Saori: *gets a little angry and stabs deeply Arkham*

Arkham: Both... demon and human blood mingle in your veins...

Saori: ... Shut up *kills Arkham*.

Arkham: *dead*

Saori: Now that the final door is open for me... you're just a deadweight for me.

The end.