Zeck's fist slammed into Slug's shoulder, but the Namekian had already braced himself for the attack, and responded by whipping his arm around as if it had no bones, slamming his own fist into the Celatian's face. Zeck flew back several meters, but managed to land on his feet.
In an instant, the battle had begun. Zeck blasted forward with the Hyper Motion technique. He and Slug collided in a blur of limbs, power, and speed that only lasted a few seconds, but carried power that blasted the air apart and speed that far surpassed what the human eye could follow.
When they finally pulled apart, neither was even breathing heavily. They paused for a second, then they went right back at it.
In the next series of exchanges, they brought the power of their blows up a notch, in exchange for speed. Zeck blasted forward, his foot a Slug-seeking missile aimed directly at the Namekian's gut. Slug shifted to the side, aiming a knee at Zeck's collarbone, but Zeck had already read the movement, and shifted to grip Slug's leg as it passed him by, slamming his fist into the Namekian's gut.
Slug's eyes bulged out of his head for a moment, before he responded with a powerful hammerblow that hit the Celatian with the force of a truck, knocking him to the ground, twenty meters below, creating a giant column of blinding light from the ki that Slug had put into the blow that trailed after him, lighting up the darkness for a moment before fading, so that the only light left was the small amount generated by the aura rolling off of the Namekian in the sky as he partially folded, grabbing his belly in pain from force of Zeck's fist, which had been stronger than anticipated, but only just strong enough to stagger him, not do much actual damage.
The smoke cloud that'd erupted from Slug's hammering of Zeck into the ground slowly began clearing, but the light from Zeck's aura was nowhere to be found.
Slug straightened, looking into the gloom caused by the giant metal ceiling he'd created. "Is that all you have?!" He shouted into the darkness, "I thought you were a warm up, but it seems you aren't even a bug! You BORE me!"
No answer. But Slug wasn't stupid. Though the Celatian was hiding in the low light caused by the giant metal 'roof' still spreading over the planet above, Slug could tell that, like him, Zeck was still holding back, at least a bit.
Unlike most born powerful, Slug wasn't the type to rest on his laurels. He believed himself to be the greediest in the universe, and that didn't just mean greed for power, but also for skill, comprehension, and raw intellectual might.
How else would one create a way of completely blocking the sun's rays for the sole purpose of increasing their subordinates' usefulness?
The Slug from before the Tree of Might fell into his lap, the ancient Slug, dying of old age, would have seriously struggled with this warrior-scientist. Zeck was genuinely that strong, in raw power alone… but the current iteration of the old Namekian didn't even need to take this level of fighting seriously. Instead, he was treating it as a form of light exercise, something that aided him in acclimating to his new youth.
This was his first battle since his age had regressed, and he had no intention of ending it early, so he pulled his punches.
Zeck wasn't stupid, either, however. He could tell. He simply couldn't tell how much power Slug was hiding under that surface.
At his current level, Zeck could literally fight indefinitely. If he pushed any further, however, it'd begin eating into his body's resources. The logical course of action was clear: To wait to power up until as much information as possible had been gathered.
The Cellatian's form flickered in the darkness, but Slug's eyes were far better in the dark than they ever were in the light. The dark was his domain. He tracked the Celatian with his eyes no matter how fast he went, or which direction.
Finally, Zeck's quick movements took him into the air, forcing Slug to turn his head to follow, as he got closer and closer. Then, it happened.
For one moment, just one single moment, Slug's eyes stopped tracking Zeck's form.
And the Celatian scientist went for the kill without hesitation. He appeared behind the Namekian, silent and quick as the wind, poised for a devastating strike to the middle of Slug's back.
A wicked smirk crossed Slug's face, as his ears twitched, tuned to track the Celatian's heartbeat with the unerring precision that his eyes and ki sense could not quite keep up with. His body twisted around for a bone crushing punch, with the fluidity that was only possible for someone for whom 'bones' were simply suggestions, or easily bendable aesthetic extremities.
Then, his fist passed straight through Zeck's body. The evil Namekian barely had the time to gasp as he realized that he'd been tricked.
The voice came from what was now behind him, a shout that genuinely felt like it would shatter his sensitive Namekian ears. "Puppeteer Strike!"
Only two blows landed before Slug's foot lashed out, forcing the Celatian to move or take a counter. Zeck's knuckle slammed into a spot just off from the center of the Namekian's back. The second blow hit near Slug's left armpit.
Both were devastatingly effective against the evil Namekian, who'd let his guard down at just the wrong moment.