Decimate the shadow

The Phantom Ursula swelled, her shadowy form expanding until she filled the upper vault of the Throne Room. She wasn't solid flesh; she was a construct of ink, malice, and dark magic, swirling like a typhoon.

"You think you can take my crown, little shark?" the Phantom screeched, her voice echoing from everywhere at once. "I am the ocean's rage!"

She spun, unleashing a torrent of black ink. It wasn't just visual cover; it was toxic, burning the water, blinding the guards, and suffocating the light.

"I can't see!" Ariel cried out, shielding her eyes as the black cloud engulfed us.

"I don't need eyes," I rumbled, my voice calm amidst the chaos.

I closed my nictitating membranes. I focused. My Ampullae of Lorenzini flared to life. The ink was dark, but the Heartless was electric. I could feel her magical signature pulsing like a beacon in the void.

"Hold on, Ariel," I commanded.

I thrashed my tail, launching us upward into the ink. "Thunder!"

I channeled lightning through my body. It arced off my dorsal fin, creating a tesla coil of energy around us. The electricity boiled the ink on contact, creating a tunnel of clear water as we ascended.

We broke through the cloud, right in front of the Phantom’s massive face.

"Surprise," I snarled.

I swung The Solar Zenith. The Keyblade smashed into her jaw. It didn't crack bone; it dispersed shadow. She shrieked, reeling back, her form destabilizing.

"Get her!" Ariel shouted. She raised her hands, weaving a spell of light. "Pearl!"

Orbs of holy light shot from her palms, bombarding the Phantom, burning holes in her shadowy dress.

The Phantom roared in pain and summoned her tentacles. They weren't flesh; they were massive chains of darkness. They whipped out, smashing pillars, trying to crush us.

One tentacle slammed into me, knocking the breath from my lungs. I spun in the water, righting myself instantly.

"Daddy! Look out!" Ariel screamed.

A second tentacle was sweeping toward King Triton, who was struggling to stand by the throne.

I didn't think. I reacted. I dove. I intercepted the tentacle inches from the King. I didn't block it with my blade; I caught it with my mouth.

Crunch. My jaws clamped down on the dark energy. I shook my head violently, tearing the tentacle completely off. I spat the dissolving darkness onto the floor.

Triton stared at me, his trident half-raised. He saw the ****, the raw power of the bite.

"Protect the King!" I ordered Ariel. "I'm going to gut the witch."

I turned back to the Phantom. She was regenerating, drawing power from the floor.

"You can't kill me!" she laughed, her voice warping. "I have hostages!"

The floor of the throne room shimmered. From the shadows beneath the throne, six bubbles rose up. Inside each one was a mermaid - Triton's other daughters. Attina, Alana, Adella, Aquata, Arista, and Andrina.

They were trapped, banging on the bubble wall, their mouths moving in silent screams. Dark energy was siphoning from them, feeding the Phantom.

"My sisters!" Ariel gasped, swimming down to Triton.

"She's using them as batteries," I realized, watching the flow of energy. "Coward."

The shark in me was offended. Predators killed to eat. Scavengers played games like this.

"Ariel!" I shouted over the roar of the battle. "Can you sing?"

"What?" she asked, bewildered.

"The resonance! Break the bubbles with your voice! I'll handle the witch!"

Ariel understood. She nodded, her face hardening. She wasn't just a princess anymore; she was a warrior's mate. She swam to the center of the room, closed her eyes, and opened her mouth.

A high, pure note pierced the water. It wasn't a song of longing; it was a sonic weapon.

The Phantom screamed. "Stop that noise!"

She lunged at Ariel with three tentacles.

"Oh no you don't," I growled.

I activated my thrusters. I became a grey blur. I intercepted the first tentacle, slashing it with my Keyblade. I dodged the second. I caught the third one in my left hand, my claws digging in deep.

I used the momentum to swing myself around, launching myself straight at the Phantom’s chest.

"Apex Strike!"

My entire body began to glow with a chaotic red aura - Shark Frenzy. I spun like a drill, Keyblade extended.

I slammed into the Phantom Ursula's chest. I bored through the shadow, tearing her essence apart. I came out the other side, trailing wisps of darkness.

Behind me, the note Ariel was holding hit its crescendo. CRACK. The bubbles holding the sisters shattered.

"No!" the Phantom wailed, her form collapsing as her power source was cut off. "I am... the ocean...!"

"You're chum," I spat.

I turned and unleashed a final beam of light from the tip of my Keyblade. It struck the dissolving mass of the Heartless. BOOM. The explosion rocked the palace, sending a shockwave that cleared the ink, the darkness, and the fear from the water.

Silence returned to the Throne Room.

I floated in the center of the destruction, my chest heaving, my gills working overtime. My grey skin was scratched, but I was whole.

The six sisters were huddled together near the floor, shaken but unharmed. King Triton was leaning on his trident, looking at his daughters, then at Ariel.

And Ariel... She swam straight to me. She didn't check on her father first. She didn't check on her sisters. She swam to me.

She wrapped her arms around my neck, pressing her face against my chest, right over my slow, powerful heart.

"You did it," she whispered. "You saved them all."

I put a protective arm around her waist, looking over her head at the King and the six beautiful, terrified, and very curious sisters who were staring at the shark man holding their sibling.

"We did it," I corrected her.

I looked at Triton.

"Your Kingdom is secure, King Triton. But the cost of protection has just gone up."