"Mitsu—" Sora panted as he suddenly collapsed to his knees, tears welled at the corners of his eyes as he looked at the girl.

"Sora—" Mitsu started as she knelt next to the teen, a hand on his back for support. Again Sora clutched his chest, his heart at Riku spoke.

"You see…the Princess' heart is responding. It's been inside you all along. Kairi's heart rests inside of you!" Riku said as he hovered in front of the ominous portal.

"K-Kairi's…heart is inside of me?" Sora asked weakly as he looked back at the girl unconscious lying on the floor.

"I know all that there is to know," Riku grinned as the sickly green energy began to flow around the teen as he looked down at the group.

"Give it up! Who are you?!" Mitsu shouted as she stood in front of Sora as if to protect him from the imposter's gaze

"It is I, Ansem the Seeker of Darkness," With a wicked grin, Riku held out his arms to exude the dark power that grew around him.

"Ansem…what a joke," Yue hissed.

"You are NOT Riku…and you're not going to take Sora's heart!" Mitsu shouted as her key blades appeared in her hands. "You'll have to go through me first,"

"Yes Princess…come to me…come to the darkness with me Mitsu," Riku sneered.

"Don't underestimate me," Mitsu spat as she stared up at the imposter.

"Mitsu—" Yasuto started when suddenly she dashed off towards Riku.

"Wait—" Shige tried to run after the girl but crashed into an invisible wall.

"A barrier?!" Yasuto said shocked as he reached out and felt an invisible wall was placed in front of them.

"Sora," Yue began. Sora glanced at the man his hand still at his chest.

"Mitsu is the eighth princess...if Ansem takes control over her, everything will end and Kingdom Hearts will be forced open, don't let that happen,"

Sora nodded as he winced and picked himself up from the floor, his keyblade in one, his hand still to his heart. He glanced to to Kairi next to the three men and then to Yue to be reassured.

"We'll protect her. This isn't our fight we'll provide support if needed,"

"She really is the Princess then," Shige said.

"Yes…"Yue replied softly. Yasuto's brows furrowed as he turned his attention to the girl fighting in front of them.

"You should have said something sooner...we wouldn't let her run around so brazenly," Yasuto commented.

"I am not here to do your job, I have my own job to do," Yue retorted.

"Your own job huh…you knew about this but didn't even bother to tell us…is that why you left from Cerun? Because of super secretive job?"Yasuto replied bitterly.

Yue glanced over his shoulder at the man before he turned his attention to Shige. The citrine haired man ignored the man's gaze as he watched Mitsu battling the white-haired teen.

Fire burned through her veins but her body felt of ice as she attacked the entity impersonating Riku. Her anger had gotten the best of her and forced her to lash out. Normally, the blue-haired teen was known for her cool and calm collectiveness but the scene now painted a different picture of her, she didn't even recognize her own self.

Her body moved on its own, as if someone has put puppet strings on her limbs and orchestrated all of her moments. She moved as if she had been trained to fight, trained to take down whatever was impersonating Riku, she effortlessly dodged the black ominous key blade. Quick in her stepped she darted around Riku only to have him instantaneously zip back and swing his key blade down in retaliation.

Mitsu dodged the blade and realized that he too fought differently than how he fought back on Destiny Island as she realized his movements were short, graceful and precise, much different when she sparred with him back on Destiny Islands.

"Give Riku back his heart!" Mitsu shouted as she threw her blades at the teen.

Riku dodged one of her blades and knocked the other back towards her. The key blade flew pass her and ricocheted off of the barrier and embedded itself into the viewing balcony above. Unbeknownst to the group below, a figure stood observing the battle below.

"The boy willingly went into the darkness in search of power to find you in the darkness, to find a way to protect you," Riku said his voice still warped. "Everything I did was to protect you Mitsu,"

Mitsu's obsidian key blade whizzed pass Riku's head and embedded itself into the wall behind the teen. Riku's aqua blue eyes gazed intently down at girl unfazed by the weapon that flew past his head. He hovered a few feet above the ground where they were engaged in battle

"Don't you dare," Mitsu growled as she held up her hand, her black key blade appeared in her hand as the white key blade in the other. Riku grinned and crossed his arms.

"Do you not want the truth, Princess?" the entity goaded her again.

"Mitsu…stop it…" Sora said weakly as he stood.

"I want to hear the truth from Riku and not from you controlling him!" Mitsu shouted angrily.

"Give me the heart princess…yours or the one inside of the boy…" Riku's voice slipped out again as he extended his hand to the girl.

"No!" Mitsu shouted.

"You're not taking anyone's heart! We'll get Riku's heart and Kairi's back!" Sora shouted from behind her.

"Very well…," Riku said bitterly as he dropped to his feet.

He pointed his key blade at Mitsu, she was his target as he was hers. Riku charged at her, again her body moved as if someone controlled it as she slid into a defensive stance with her key blades in hand and readied herself.

Just as Riku raised his key blade to strike time around Mitsu and Riku began to slow down to a crawl and then stopped completely. At that moment a female voice that she heard so many times spoke to her.

A heart surrounded in darkness is not a lost cause.

Embrace it with your warmth.

Embrace it with your will.

Embrace it with the light in your heart…

It will take some time…

But surely, your heart will be its guiding key back to the light…

Embrace it

Despite the intense battle, despite how her body felt as if it was on fire, everything led up to this point, her sacrifice.

"May my heart be your guiding key…Riku," Mitsu said as she dropped her key blades and held her arms open as if to embrace the teen.

Embrace him.

"Riku…" Mitsu smiled

"No! Stop-!" Yue started. Sora stumbled up to his feet and ran towards his friends

"Mitsu!" Sora shouted as he ran to her his arm extended out to her as if to reach for her.

The black key blade struck her across her abdomen and then sank into her chest instantly Mitsu's eyes dulled and her head rolled back as a light grew from her chest. The wicked grin plastered on Riku's face faded as the light grew from Mitsu's chest, he tried to step back and shield his eyes but remained frozen.

"W-What?!" Riku shouted.

The light from Mitsu's chest engulfed the room as shouts of pain and agony echoed through the light. When the light diffused Riku was on his knees, his breaths labored as a cloaked figure cried in agony as it stumbled away.

"Mitsu!" Yue shouted as his voice cracked as he darted off towards the girl, Shige and Yasuto behind him.

Mitsu's body hovered slightly off the ground as she fell back, whips of light and dark tendrils flowed from her chest as the black key blade fell from her chest and clanged to the ground. A faint pink light rose from her chest and enveloped Riku, a short gasp came from the teen as warmth shot through his body.

The silent and ominous looking portal, a pathway to the fabled Kingdom Hearts cracked to the point of nearly shattering and started to bubble furiously. Riku held his chest as he looked painfully at the girl floating lifelessly.

"M-Mitsu's heart?" Riku gasped as his breaths were still labored.

Mitsu's body began to lower itself onto the ground as Sora ran over to her. Just as her feet touched the ground her body was taken up by another cloaked figure, with Mitsu over their shoulder they jumped back on to the viewing balcony.

"What?!" Sora shouted.

"Let her go!" Shige roared.

"Oh? Why's that?" the person asked.

"Let her go!" Sora and Shige both shouted at the unknown person.

"If you insist…" the person trailed off and held Mitsu over the ledge by her ankle. Yasuto took a step forward as he noticed something falling from the balcony, but then quickly turned his attention back to the girl hanging upside down.

"What the fuck are you doing?!" Shige shouted.

The person laughed and carefully placed her back on to his shoulder and looked down at the angry men.

"What do you want with her body?" Yasuto shouted

"A theory that we would like to test. But don't worry I'll keep her safe. I promise cross my heart and hope to die" he replied.

"Who is we?" Yue shouted furiously.

"That's a secret," the person said and wagged his finger.

"Get down here and let Mitsu go!" Sora shouted.

"Sora was it? If you want the girl back…Castle Oblivion is where you need to go," the person replied.

"Castle… Oblivion?" Yasuto repeated confused.

"…Castle Oblivion…" Riku repeated weakly.

"Castle Oblivion, Got it memorized?" the person said and pointed to his head.

"Let her go!" Yue shouted.

"Man you sure are noisy…anyways…ciao!" the person said as he stepped away from the ledge.

"Mitsu!" Shige shouted

"Wait no!" Sora shouted

I hear voices calling out to me…but I can't respond…is this what he was talking about?

May my heart…be your guiding key…Mitsu…