Bui's body bursts with more green battle aura, though not nearly as much as before. He raises his head and blankly stares at Adrien.
"You can never have the last of something self-replenishing. If it were that easy, I wouldn't need to wear my armor."

(Karutomaru isn't there.)

"Fine then. Kill me."

"What do you expect me to do then?"

"You expect to fight on equal terms while I'm bound?"

"Probably, but I think I can handle it. It wouldn't hurt to go all-out though."
Bui's battle aura pulses, and his bindings weakens.

"Alright then..."
Bui floats into the air once again.

"Try dodging THIS!"
Bui grabs his shoulders ad then stretches out his arms. A cross-shaped collection of battle aura is formed and fired.

(Skybox? What?)

The blade deflects the blow into the air, but the cross comes back down on Adrien's location. Bui floats to the side and avoids the cut.
"That attack isn't meant to miss."

Bui cuts Adrien off and holds his hands out.
"Going somewhere?"

The blast connects with Bui and explodes in a light show of green lightning and smoke.
Unable to see in the carnage, Adrien is struck to the side as the smoke clears, revealing Bui to be relatively unharmed, but breathing rather heavily.
"Very clever. But it only uses as much power as needed to kill my opponent."

"I was told the competition here would be worthy of my strength. It's unfortunate I was matched with such a dishonorable opponent."

"That belief is why you don't deserve mercy."

"We'll see about that."
Bui holds his hand up. Red lightning circles and focuses on his palm.
"I was saving this for a special occasion."

Another axe materializes in his hand. This one, though large, is significantly smaller.

"Karutomaru gives us the most interesting toys."

"And that's not all."
Bui throws the axe horizontally at Adrien. Adrien attempts to move out of the way, but his feet suddenly feel like 50 pound weights.

The shield sparks when the axe slams against it and deflects away from Adrien. The relief of the moment is squandered when the axe circles back around.
Adrien notices his feet feel lighter after the axe's impact.

Bui crosses his arms and watches the axe move on its own.
"It's a very special weapon, possessed by the guardian that made it."

The spinning axe turns into red lightning and returns to Bui's hand.
"You don't believe me? I can introduce you to him right now."

Bui throws the axe into the ground. A spirit emerges and materializes from it.

The guardian picks up the gravity axe. Bui brings his own axe to his hand and holds it with little effort. Without his armor, he isn't pushed into the ground.
"I'm done playing games. Let's finish this."

"Get his left!"
Bui runs in an arch to Adrien's right. The guardian arcs left. They're going too fast, and Adrien feels too heavy to run away in time.

The guardian is shot and shatters like glass. Gravity returns to normal, but Bui's axe is at the ready a few feet behind Adrien. Bui wields it one-handed with almost no effort.