Rimuru and Ultima Goes To One Piece (Rimuru and Ultima x One Piece)

Chapter 5: Entering the Grand Line and Reaching Karakuri Island

The Tempest Pirates were sailing through the calm but unpredictable waters of the Grand Line, their ship cutting effortlessly through the waves. Rimuru stood at the helm, his eyes scanning the horizon with a sharp intensity, while Ultima lounged on the deck, her eyes closed in quiet contemplation. Both were still buzzing with excitement from having crossed the legendary Reverse Mountain and officially entering the Grand Line.

Ultima: "So this is the Grand Line, huh? Doesn't seem so terrifying just yet."

Rimuru smirked at her comment, but he knew better. The Grand Line was famous for its wild weather, unpredictable islands, and powerful opponents. Despite the calm seas, he knew it could change in an instant.

Rimuru: "We've barely scratched the surface, Ultima. Just wait—it'll get much more interesting soon enough."

Suddenly, Azura's voice echoed in their minds, breaking their moment of peace.

Azura: "Master Rimuru, Mistress Ultima. There's something you'll need for your journey here in the Grand Line."

Ultima opened one eye, intrigued, while Rimuru gave a slight nod.

Rimuru: "What is it?"

Azura manifested in front of them in a small flash of light, holding a small device in her hand. It was a Log Pose, the compass-like tool necessary for navigating the Grand Line. Unlike regular compasses, which didn't work in this bizarre sea, the Log Pose was attuned to the magnetic fields of each island.

Azura: "This is a Log Pose. It will point you to the next island by locking onto the magnetic field of the current island you're on. Without it, you'd be lost in these seas forever."

Ultima raised an eyebrow, taking a closer look at the Log Pose in Azura's hand.

Ultima: "So we really can't just sail blindly? I was hoping for a little more chaos."

Azura shook her head.

Azura: "Chaos or not, the Grand Line operates by its own rules. If you want to survive here, you'll need this. Consider it your guide."

Rimuru reached out and took the Log Pose, inspecting it for a moment before strapping it to his wrist.

Rimuru: "I'll be the navigator, then. With this, we can plot our course without any issues."

Ciel, who had been quiet up until now, chimed in.

Ciel: "I'll help you, Master. Together, we'll ensure smooth sailing, and I'll analyze the Log Pose's magnetic readings to predict upcoming weather patterns."

Ultima let out a sigh, stretching her arms lazily.

Ultima: "Fine, fine. Leave the boring stuff to you two. I'll focus on the fun part—getting stronger and taking down anyone who gets in our way."

Rimuru smiled, knowing Ultima's personality all too well.

Rimuru: "Don't worry, you'll have plenty of opportunities for that. But for now, we need to follow this Log Pose and see where it takes us."

With their course set, the Tempest Pirates sailed onward. The first few days passed without incident, giving them ample time to continue their Haki training. After all, in a world where Devil Fruits and Haki defined the strongest fighters, Rimuru and Ultima knew they couldn't afford to fall behind.