Thirty minutes later, Tiona and Tione met at the entrance.
Their weapons and limbs were smeared with blood, yet both sisters looked relaxed. After clearing out the Dark Faction troublemakers who had planned to interfere, the upcoming battle against the Floor Boss felt much lighter.
"All done?"
Tione glanced at Tiona's Urga. Faint streaks of red still lingered on the blade—blood that hadn't been completely shaken off.
"Of course it's done."
Tiona flexed her arm with a grin, showing off her muscles as if it were the most natural thing in the world.
Ignoring her, Tione turned her gaze toward Tsuna.
"You should thank Tsuna for covering for you. Otherwise, with your fighting style, the whole floor would've been in chaos by now."
Tiona's proud smile stiffened. She puffed out her cheeks and glared at her sister.
"Tione, can you not ruin my mood when I'm feeling good?"
"That's not ruining it. I'm just stating facts."
"Ugh!"
The two sisters faced off again, puffing up in irritation. Tsuna could only shake his head helplessly—these two were always bickering.
"Tione, how's your side?"
"Perfectly handled!"
The moment Tsuna spoke, Tione dropped her squabble with Tiona and turned to him with a gleam of focus.
"The firestones scattered near the entrance and exit have all been dealt with."
"The ambushers there were taken care of too."
"No one escaped, and all the planted firestones have been removed."
"Good work, Tione."
Tsuna nodded slightly at her report, not stingy with his praise.
Tione's face immediately brightened into a smile.
"Tiona, Tione—next comes your battle."
Tsuna's lips curved in a faint smile before his expression grew solemn. A Floor Boss subjugation was never something to take lightly.
The sisters' faces hardened as well.
"Given the current state of the Great Fall, you'll be at a disadvantage against Amphisbaena."
"In water, that dragon holds a tremendous edge—an advantage we Adventurers simply don't have."
Tsuna's tone was serious as he laid out their situation.
"But you two also have advantages of your own."
He pointed at the rings on their hands.
Tiona and Tione glanced down at the rings they wore. The tense air eased slightly.
"That's right. We've got something that dragon doesn't."
"Not just the rings—our gear too. All custom-made by Tsuna himself."
Tiona raised her hand with excitement, showing off the ring, while Tione tugged on her shoulder strap with pride.
No matter how dangerous Amphisbaena was, they had Tsuna's support behind them. That was a strength no Floor Boss could match.
Seeing their confidence reignite, Tsuna's own tension finally eased.
"Then, I'll summon it."
"And that will mark the start of your challenge."
"Right!"
Both sisters nodded in unison.
Tsuna activated the preparations he'd long since completed.
A deafening boom erupted above the waterfall. What had been a gentle stream moments ago suddenly swelled into a roaring cascade.
The water level below rose sharply—more than two meters high—leaving only scattered rocks poking above the surface. The stage was set.
From the depths, a pair of crimson eyes snapped open. Each eye was as large as a man, glaring ferociously at Tiona and Tione, as if ready to swallow them whole.
Boom!
The next moment, the surface exploded like a detonated charge. Torrents of water crashed over the few rocky footholds.
Tiona and Tione leapt up in time—each to one side—gripping the walls with their hands to barely avoid being swept away.
"This thing's giving us a warning before it's even shown itself."
Tiona's eyes locked onto Amphisbaena, both heads now breaking the surface.
"Stay calm, Tiona."
"This is the toughest opponent we've faced yet."
Tione dared not let her guard down. Without any terrain advantage, facing Amphisbaena was a grave handicap.
But precisely because of that, this was their challenge to claim.
As they spoke, a flicker of azure flame shimmered across the water.
"!?"
"Move!"
Tione shouted, springing away from the wall.
A jet of blue fire shot from the surface, striking the cliffside. The solid rock instantly glowed red-hot, melting into droplets that sizzled as they fell into the water.
Zzzzz!
Steam hissed violently as the molten rock hit the surface, forming a thick mist of scalding vapor that blanketed the arena.
The water dragon crouched atop the surface, unaffected—the white steam shielding it instead of harming it.
Its armored scales easily resisted the heat's corrosion.
Twin golden slits scanned warily around it, searching for any sign of the Adventurers.
Splash, splash, splash—
Footsteps rippled across the surface. Instantly alert, Amphisbaena's right head turned toward the sound and spewed a cloud of Red Mist.
The footsteps in that direction grew heavier, slower.
Then, the left head gathered another burst of azure flame and unleashed it toward the sound.
The flame's shockwave blew away the mist, revealing—nothing.
"!?"
The dragon's twin pupils contracted. The left head couldn't halt its attack, continuing to fire blindly.
Meanwhile, the right head scanned frantically, searching for the two humans.
There!
Above!
The right head looked up just in time to see a human descending rapidly, twin blades raised high.
The left head jerked upward, blue fire sweeping erratically through the air.
But the sudden shift threw its aim off completely.
And at that moment, footsteps splashed from directly ahead.
Tione charged across the water, her left arm seared and useless, her right gripping her kukri tight.
Berserk—activate!
Backdraft—activate!
"Can't move now, can you?"
Her kukri cut straight for the left head's throat—the very instant when Amphisbaena's own fire left its weak point exposed.