Nico Robin Adventures P3*

Robin POV:

*Huff Huff*

Robin ran and ran through the foggy domain as her life flashed before her eyes like a movie. It was as if there was no end to the fog and danger loomed at every step, these mindless ghosts were very dangerous too. If they get too close, they will start absorbing all her dreams and happiness like demonic leeches. Even though they are harmed by armament Haki, she can't keep fighting hordes of them at the same time.

Her lovely mother, Nico Olvia who sacrificed herself to save the books inside the Tree of Knowledge.

Her mentor, Professor Clover who took her into his care when she was ostracized by the other children who called her a monster due to her ability.

The archaeologists in Ohara who were like her family when her own aunt treated her like a slave.

That nightmarish night when she lost all her family and acquaintances in that single nightmarish night.

"Give up Robin, why are you still resisting? Give up and we can finally be together!!" There was a sweet voice in her head resembling her mother's which was urging her to let go. But she knows this is all mind games to break her will. 

Even though she knows all this, it doesn't mean she was not affected. It opened up her old scars and vulnerabilities evident from the tears in her eyes. 

Itzel who was observing all this looked at her thoughtfully. He suddenly appeared in front of her,

"Stop running miss Robin," His golden halo shone brighter as the mindless ghosts who were chasing her screeched demonically as they retreated into the fog. Robin watched this with relief as she collapsed on the ground.

"Who's Victor?" He asked suddenly causing her to look up questioningly. "He has come to save you but it seems Kusanagi has taken a liking to him. He's going to become his next vassal."

Robin who heard this was shocked momentarily, "How do you know this?"

"As the demon's vassal, I can share his vision. This boy tried to fight with Kusanagi but I guess he's not strong enough."

"Why is he here? What's happening outside?" Robin asked worriedly. She now regrets sending a message to Victor asking him to come. Even though Victor was strong normally, she doubts he can defeat a Demon King on his own.

"Kusanagi has agreed to let you go but it's obviously not for free."

"There is a price! What is it?"

"A sacrifice of your humanity. When Kusanagi selects a new vessel to possess, it looks for a strong-willed person. The demonic power corrupts your soul as the host faces his worst nightmares until the vassal is a mindless killing machine completely under its control. When you realize what you have done under its influence, it's too late and you have already lost everything you cherished."

"Then how are you still sane?"

"Two hundred years ago, do you want to know what happened in the final battle?"

(200 years ago)

[Prince Izel watched from the pinnacle as civil war raged on Mexica, the other tribes were marching toward the pyramid as the populous of Mexica also joined them. His forces were fighting back but it was evident that this was a last bit of struggle. Meanwhile, he could feel the power coursing through his body as the souls of the dead were being absorbed by Kusanagi, the cursed demonic sword.

"Hiss!! My King, Princess Izel is holding her ground, but we won't last much longer. The people demand answers and blood," Tlaloc, the treacherous advisor, hissed in Itzel's ear. His dreams to see the world burn has come to fruition. Once his master Kusanagi completely controls Itzel, he has promised him the power of immortality and endless power.

The once majestic Mexica was now a battlefield of despair. The curse had twisted everything, and the kingdom was tearing itself apart. Itzel, driven to the brink by the malevolent force within Kusanagi, felt a cold detachment from the chaos around him.

"Hiss!! My KING, we must end this bloodshed once and for all," Tlaloc continued with a sinister glint in his eyes. "The power within you is immense before these measly flies. With every soul you consume, the world will slowly descend into darkness. Embrace this darkness, and your enemies will lay at your feet."

Itzel's grip tightened on the cursed blade. The whispers of the souls within echoed in his mind, urging him to yield to the demonic power. But a flicker of resistance remained. Memories of love, of Mexica's prosperity before the curse, and of Princess Izel's unwavering hope for a better tomorrow still lingered in the recesses of his consciousness.

"No, I must stop the war, for my dear Izel," Itzel muttered, his voice a strained whisper. "I won't let Mexica fall further into darkness."

His resolve sparked a moment of clarity. With a surge of will, Itzel confronted Tlaloc. The treacherous advisor, realizing his plan was unfolding also drew his own blade.

"Itzel, don't resist. I was the one who brought Mexica to such great heights, without my help you were just a young brat." The clash echoed through the pyramid's sacred chambers, a desperate struggle for the fate of Mexica.

As the battle waged on, Itzel could feel Kusanagi's influence intensifying. The cursed blade hungered for more, demanding the sacrifice of thousands of lives to become an unstoppable force. Itzel fought not only against Tlaloc but also the insidious whispers of the sword in his mind.

*Swish* 

Suddenly a spear made of golden light was thrust into his chest as he saw the beautiful Princess Izel in her warrior attire and hybrid angelic form hovering in the air. She has returned from her journey through the Grand Line and found a cure to the curse, a devil fruit that can counter cursed demonic energy. (Hito Hito no mi: Angel)

"It has been a long while isn't it Kusanagi? Now you'll pay for what you have done to Mexica, our people." She said angrily as she looked at him with deep hatred. 

"Izel? How are you still alive?" Itzel was in shock, Tlaloc had told him Izel was murdered by the enemy kingdoms after she ran away a few years ago. 

She had warned him about the curse but his mind was so clouded and corrupted by greed, anger, and evil that he didn't even pay attention to her. It was a deep regret that drove him further into madness, he enslaved prisoners and forced them to build the huge pyramid in her remembrance and filled it with riches he gained after the bloody wars. He was so corrupted with madness that he even cut off the hands of the artisans and laborers so that no similar building was built again. This was the thing he wanted to protect most, the epitome of his 'deep' love.

"Kusanagi, I won't let you wreak havoc in the world anymore. Grandpa Tlaloc, run away from here, I'll handle it." Izel activated her powers as shining spears with golden glow appeared and rushed towards Itzel. He tried to block but the huge force caused him to grit his teeth in pain.

"Izel, It's me..." He tried to speak but the pain and emotional fluctuations caused Kusanagi to overpower his mind and take control as he watched in horror. 

[Bwahaha! Love and emotion make a man WEAK!!! Itzel, let's make you truly strong as I promised.]

Kusanagi activated his vessel devil fruit powers and he started to transform into a monstrous flying serpent, Quetzalcoatl. A plumed, two-legged, winged creature with a serpentine body, resembling a cross between a dragon and a bird. 

An intense battle raged on for two days and Princess Izel was finally successful in defeating Kusanagi but she was heavily injured in the process. As Kusanagi's monstrous form dissipated, the pyramid's sacred chambers echoed with the aftermath of the intense battle. The cursed sword's influence waned, leaving Itzel in a weakened and disoriented state. Princess Izel, with her injuries, hovered near Itzel, concern etched on her face.

"Itzel, can you hear me?" she whispered, her voice filled with a mix of relief and exhaustion.

Itzel's eyes flickered, a hint of recognition breaking through the haze of the curse. "Izel my love... I'm sorry... for everything." He said before he spat out a mouthful of blood. Tlaloc, having observed the entire struggle, chose this moment to crawl out from the shadows.

He looked at the weakened Itzel and the injured Prince Itzel with a twisted grin, sensing an opportunity even in the midst of defeat he fired an arrow that pierced Prince Itzel on his back causing him to grunt in pain.

"You may have defeated the vessel, but Kusanagi's curse will persist. I shall finish what I started," Tlaloc taunted, drawing another arrow. His eyes were bloody red as the curse took over his old body.

However, as he prepared to take aim and fire, a surge of energy erupted from Izel. Despite her weakened state, a newfound strength coursed through him that put immense pressure on Tlaloc and the approaching enemies.

"I won't let you cause more harm demon," Izel declared, her eyes glowing with a determined light. Princess Izel, despite her injuries, mustered the strength to stand between the weakened Itzel and the treacherous Tlaloc. Her body radiated with a dim, golden aura as she summoned the last remnants of her powers. Six wings appeared on her back with multiple eyes on them.

"See you in the afterlife my love." She said with a sad smile and performed her ultimate attack. (Divine Sealing) absorbing the demonic powers of Kusanagi and sealing most of them inside her as she healed Itzel with a golden glow. Before she could finish though, her body gave away and she fell lifelessly on the ground before Itzel's shocked eyes.

"Noooooo…." He cried out in despair as his eyes turned red with grief, sadness, anger, and various chaotic emotions. In the moment of anger, he rushed towards weakened Taloc and sliced off his head.

]

"The demon had tried numerous times to get a new host but Izel's holy power had sealed most of its powers. To repent from my sins I guarded the tomb for 200 years wielding the curse," Itzel said somberly. "The remnants of the populous fled Mexica after the bloody war and since then many robbers and pirates raided this place driven by greed. The wild beasts kept most of them at bay. If someone unfortunately opened the gates the curse tried to take control over them but most of them died in the trials as they couldn't bear the demonic power. Those who survived became mindless beasts and I had to eliminate them to stop the curse from spreading to the outside world."

"How to stop this? There must be a cure." She was really shocked, she had never imagined that her hunt for poneglyph would lead to such a tragedy. She felt a pang in her chest when she realized that she was responsible for Victor's suffering.

"Sheer willpower can subdue the curse but to end this curse you will need to destroy the source."

"What's the catch? Tell me where can I find the source of the curse?" Robin found a ray of hope in the darkness and she wasn't going to lose her loved ones again, that too because of some bastard old ghost. 

"Me, I am the source of the curse. You have to kill me and defeat Kusanagi at the same time, but once you draw hostile intentions, it will alert the demon Kusanagi and it will fight back." Itzel said with a sad smile but there was also cold oppression that filled the air.

Many thoughts rushed through her mind and she questioned, "Why are you helping us, Prince Itzel?"

"Hope, I can only hope that I can meet my Izel again after my curse ends. The power of immortality may sound tempting but without any loved ones around you It'll only become a hellish nightmare." He said, his voice filled with sorrow and regret.

"Now you have a choice you have to make. You can either fight back which won't be easy or sacrifice your lover and get away safely. I can even tell you the location of the hidden poneglyph. Let me sincerely warn you, I am not easy to kill when Kusanagi takes control."

Robin's eyes widened with shock when she heard this but it soon turned into determination.

"There are many poneglyphs, but I only have one husband. I'll end your curse once and for all."

"Great!! Since we have cleared the first step we have to inform Victor before it's too late." He said thoughtfully. He could try to take over his body but it would alert the demon.

"I can try one thing, I don't know if it will work," Robin said with determination as she took a sharp blade and stabbed it into her hand.

**

*A/N : 

Guys, someone in the comments questioned if this is still a One Piece fanfic. I would like to clarify that I took inspiration from Tot Musica from the One Piece: film Red. Demon Kings and cursed swords do exist in cannon and non-cannon, so I tried to spin a tale around it to create something different. It will only exist in this arc so please bear with it till the next chapter.