A blue Aura Sphere gathered between Lucario's palms.
"Aura Sphere!"
Lucario released the sphere, and it collided head-on with Greninja's Water Shuriken in midair.
Boom!
Thick black smoke bloomed outward, and Greninja dropped back down to the ground.
"Slash!"
Ash swung both arms up and down.
Gripping a white kunai, Greninja settled into a stance and charged forward, closing the distance to Lucario with a single powerful kick-off.
Lucario clenched a fist in midair, blue specks of light gathering in its palm until a Bone Club took shape.
Bang!
The Bone Club and kunai clashed again, throwing off sparks. Lucario flicked its wrist, batting Greninja back several meters just as it lunged forward for what looked like a finishing blow.
But two more kunai came flying in. Lucario dropped the leg it had just planted, spinning the Bone Club in one hand to knock the kunai aside, one after another.
Greninja flipped and landed, palms glowing white as it shot forward.
"Aerial Ace!"
Catching Lucario mid-motion as it drew its club back, Greninja snapped off a light uppercut that caught Lucario clean on the chin. Lucario's feet left the ground, its head tilting back, brows furrowed against the sting.
"Slash!"
Greninja pressed the advantage, white light gathering in its palms as two fresh kunai formed in its hands. It spun through the air and landed a clean cross-slash.
Bang!
The blades struck Lucario square in the chest, and it fell backward, rolled once, and ended up half-collapsed on the ground.
"Lucario!"
Lucario snapped its head up and slammed a palm against the ground. Five Bone Clubs, glowing with earthy yellow Aura, floated into position around it. Lucario snatched up two, one in each hand, and swept the rest aside with a single motion.
"Greninja, dodge!"
With sharp, agile movements, Greninja weaved past three incoming Bone Clubs before gripping its kunai and charging Lucario head-on.
Bang!
Lucario crossed its two Bone Clubs, catching Greninja's thrusting kunai between them.
"Low Kick!"
Lucario's gaze dropped to Greninja's legs. Since Ash shared Greninja's field of vision, he caught the same telltale glance.
"Jump, Greninja!"
Greninja hopped lightly, tucking its legs up to clear Lucario's sweeping Low Kick, then twisted sideways in midair and drove both feet into Lucario's crossed Bone Clubs, forcing it back several steps. Lucario planted its rear foot and steadied itself.
"Water Shuriken!"
Greninja landed and hurled two blue shuriken, which split apart in flight into five spinning blades.
"Extreme Speed!" Steven called out.
Lucario tossed its remaining Bone Club aside — it struck the ground and dissolved into particles of energy — just as the Water Shuriken passed clean through where Lucario's body had been. In an instant, Lucario's outline had gone hazy, then vanished entirely.
Greninja froze, a chill of danger crawling up from behind. It spun around and stabbed backward on instinct.
Bang!
Lucario's fist had already found Greninja's side, sending it tumbling through the air before it crashed hard into the ground. Ash's face twisted in pain; he dropped to his knees, clutching his own side, breathing hard.
Faint motes of light still hung in the air where Greninja had been standing. Slowly, they drifted into Lucario, mending some of its wounds.
"Gra..." Greninja pushed itself back up, eyes locked on Lucario.
"Let's finish this, Lucario — Close Combat!" Steven's voice had settled, calm now. Ash and Greninja still had plenty of room left to grow. There was no reason to push things further than necessary.
Fighting through the pain, Ash forced himself upright and pumped a clenched fist. "Water Shuriken!"
Lucario closed the gap with Extreme Speed and threw a punch.
Clang!
The sound of a fist meeting flesh never came. Confusion flickered across Lucario's face — its fist had struck not Greninja's body, but a massive shuriken held up in defense, Greninja's steady eyes visible just behind it.
Lucario's Close Combat wasn't finished, though. It swept a kick low, which Greninja cleared by jumping, then twisted sideways to dodge a downward slash from the shuriken, before pivoting back to drive a kick into Greninja's stomach, sending it flying once more.
The instant Greninja hit the ground, it looked up to see Lucario already airborne, descending fast with a single, sharp kick.
Bang!
Greninja rolled desperately out of the way. Before it could rise, Lucario, still carrying the momentum of its kick, fired off an Aura Sphere.
Boom!
With no time to dodge, Greninja thrust its kunai straight into the incoming sphere. The two collided in a burst of energy, and billowing white smoke swallowed Greninja from view.
Steven didn't bother watching for Greninja inside the smoke — Ash's condition told him everything he needed to know. Ash could no longer stand, slumped on the ground and gasping for breath. The battle had to be over now... didn't it?
Then Steven caught sight of a shape still standing within the smoke, and his breath caught. Somehow, Greninja was still on its feet — and by its posture, it hadn't dropped out of its Bond Phenomenon with Ash.
As the smoke cleared, both Steven and Lucario could see the fierce refusal in Greninja's eyes, the sheer unwillingness to accept defeat.
Bang!
Then Greninja's eyes slid shut, and its body pitched forward. A white glow washed over it as it reverted to its base form and dropped to the ground. It could no longer continue.
Steven let out a breath, relieved — for a moment, he'd genuinely wondered if Greninja might keep fighting on willpower alone. But the Bond Phenomenon demanded even more stamina than Mega Evolution, and it pushed a trainer's body far harder besides, since the pain crossed over to Ash just as truly as it did to Greninja.
Setting Ash aside — a trainer with the Heavenly Physique needed no further explanation — the only other people Steven could imagine enduring that kind of strain were Jessie and James. Between Jessie catching Pokémon with her bare hands and the two of them surviving explosion after explosion while chasing Pikachu without serious injury, their toughness spoke for itself.
"You did well, Lucario." Steven walked over and gave its shoulder a pat.
"Lucario," it replied evenly, then returned to its Poké Ball.
Steven turned and made his way toward Ash on the other side of the field.