Hein planted a boot into the street, the paving stones cracking under the pressure. Using the rebound he hurled himself back toward the arena like a missile, his aura blowing apart nearby stalls and houses as he went. Wood splintered, canvas tore, people screamed and scattered.
In a blink he was in front of the King again, teeth bared.
"Hey," he growled, sword raised high, "don't you wanna know your future killer's name?"
The King, still weaving through the chaos, barely tilted his head. "If you say so. Tell me."
Hein grinned. "It's Hein."
He swung; a blade of force ripped the air apart. The King slipped aside and drove a heel into Hein's ribs. The blow sent the assassin crashing into the arena's rooftop in an explosion of dust and tiles.
Snarling, Hein pushed himself out of the rubble and bellowed toward the sky. "Dyna! Why aren't you here yet? Stop wasting your domain on useless people, huh? And Nene—stop playing around!"
Inside the shimmering black sphere of her domain, Dyna's eyes twitched with irritation. "Ahhh… fine. Coming."
She flicked a glance back at the frozen Leo and Zama. "Just wait here. I'll be back in a few minutes." Then her form blurred, dissolving out of the barrier.
Before the King could shift his stance, she was already behind him. Her palm slammed into his back like a thunderclap. The impact hurled him down into the arena roof, shattering stone as he hit.
A moment later the King rose again from the dust, cloak settling around his shoulders, eyes narrowed. "Huh," he murmured, brushing debris from his arm. "She's fast."
Here's a version of that moment written so it feels like the scene you described but also gives the King his "aura-farming" entrance and a fitting name/title:
The King twisted in mid-air just as a monstrous maw snapped shut where he had been a heartbeat before. The crimson lining of his cloak shredded, fluttering away like sparks, but he didn't even glance at it. Hovering above the wrecked arena he swept the battlefield with cold, sharp eyes.
That puppet magic again… whoever's controlling it is far beyond ordinary mages.
A glint flashed; Dyna's blade hissed past his cheek, close enough to draw a hair-thin scratch.
Tch. Focus.
He shifted his weight, about to drive his heel into her back when a thunderous blow slammed into his ribs — Hein. The impact hurled him toward the edge of the domain.
No. If I get dragged inside, it's over.
At the last instant the gigantic puppet lunged for him again. He planted a foot on its gaping jaw, using it like a springboard. The beast snapped shut and was sucked into the domain, pinned there, while the King launched himself higher, free. Below, Nene lunged from the shattered balcony trying to pull him in, but her hand closed on empty air.
He hovered above them all, breathing once, crimson eyes glowing brighter. Golden hair whipped in the gust now circling him. The temperature dropped, clouds began to churn; the very weather bent toward him.
A slow, dangerous smile curved his mouth.
"Enough," his voice rolled across the arena like thunder. "You've had your turn. Now… it's mine."
Lightning crackled over his outstretched arm as he raised his hand. "Remember this moment, assassins. You stand before Aurelius Rauthveil, the King of Rustalia."
His aura burst outward, a tide of red and gold, swallowing the morning light.
As Aurelius spoke his name the air cracked. He thrust one palm toward the sky and a blinding, golden sigil blossomed above the arena, so vast it seemed to blot out the morning sun. Lines of power spun outward, runes igniting like stars. From the circle's heart, colossal swords of pure light began to manifest one after another, hanging in the air like a rain of judgment poised to fall.
Below, Dyna's smile vanished. Hein's face tightened. Even Nene stopped playing with her puppet. The killing intent rolling off the King was no bluff; if those blades descended, none of them would leave alive.
"Tch—Nene!" Hein barked, eyes darting. "We're pulling back. Now!"
Dyna flicked her fingers and the dark domain dissolved with a hiss. In the same instant Leo and Zama dropped to the arena floor, gasping, colour returning to their faces after being unable to breathe inside the field.
The monstrous puppet lumbered free of the collapsing domain and scooped Nene up from the balcony. With another bound it collected Hein and Dyna; the three assassins crouched on its back as Dyna raised her hand and tore open a swirling portal.
They vanished into it just as the golden swords overhead pulsed brighter. But Aurelius did not release them. His crimson eyes narrowed; the circle dimmed, the blades faded. Good. They're gone. He lowered his arm slowly. If I'd unleashed that here the arena would be rubble.
His gaze shifted to the two figures still sprawled on the stone. The King descended, boots touching down with a soft crack of energy, cloak trailing in tatters behind him. He regarded them with a frown, unable to sense any obvious malice.
"You two," his voice lost its thunder but kept its edge, "are you all right?"
Leo froze for a heartbeat when he heard the King's voice. So…Aurelius. That's his name. But I have to—
Before the thought could finish, Aurelius looked straight at him and said gently, "Leo, are you all right?"
From behind the mask, Leo's eyes went wide. He turned his head sharply; Aurelius had already let a fraction of his guard down, a faint smile tugging at the corner of his mouth. "Oh… you don't know that I know you're Leo?" the King said almost teasingly.
Leo instinctively shifted back a step. "So now, when you already know us, I don't think I should let my guard down, correct?"
"It's fine," Aurelius replied, tone calm but sure. "If I truly wanted to attack you, I'd have done it while you were trapped inside that assassin's domain."
Zama immediately stepped in front of Leo, eyes hard and body tense, imagining dark motives. But Aurelius didn't even blink. "Zama, correct?" His crimson gaze softened. "Look—if I had ill intent toward your lord, I'd have struck the moment you called him Leo. Or when you were both paralysed. This is my arena; if I meant to kill you, no one would ever know."
Leo exhaled and, from behind, finally tugged off the mask. "It's okay, Zama." Then, tilting his head with mock irritation, he added, "And by the way—why did you call me Leo?"
Zama stiffened. "My apologies, Lord Leo, but calling you Hades doesn't fit you."
"Huh?!" Leo blinked. "What do you mean 'doesn't fit me'?!"
Aurelius chuckled at the exchange, a rare warmth in his face. "You two can argue over names later. Come to my castle; it's safer there."
Leo scratched his head. "Ah… anyway, what do you want, Aurelius? Wait—he's the king, right?" He straightened awkwardly. "I mean… King Aurelius."
"It's fine," Aurelius said with another small smile. "You can call me Aurelius."
Then his expression turned thoughtful. "By the way, where is Arvaris? I sent him to bring you here. You're already here, but he hasn't shown up. He left long ago."
Leo's brow furrowed. "Arvaris… that guy was looking for me?"
"Yes," Aurelius nodded. "I sent him myself. Yet it's been some time and still no sign of him."
"Wait—" Leo lifted a hand and tried to reach Lili through his link, but nothing answered. His heart dropped. "Oh no…"