Tarble had been the first one to notice it, during his research into Saiyan S-Cells.
Whatever 'god' designed the DNA blocks that made up 'people' in this reality was an exceptionally lazy one.
Most humanoid races in this reality had almost identical structure to their bodies.
In fact, one could even take that further.
Celatian DNA had 25 distinct chromosomes. 23 of those were within possible parameters for human DNA. Saiyan DNA was similar, but with 26 chromosomes.
In other words, whatever 'creator god' had designed Saiyan and Celatian biology had essentially taken the human form and simply integrated extra racial features.
Did that extend to other 'humanoid' races, like Namekians?
It could be expected that the answer was 'yes', at least partially. For the most part, the body's physical structure was fairly similar. Definitely not identical, but similar. Bone structure, organ placement, two eyes, two ears, two lungs, brain in the right place, spine was just as essential for bodily functions… All of this was evident at a glance, to an eye as experienced with the human form as Zeck, who'd been crazy enough to implant an energy converter into his own body.
Which meant that he didn't hesitate to use several of the techniques that he had specifically designed for use against other humans, against the Namekian warlord.
His first blow was a knuckle just off of the spine. It wasn't a particularly strong blow, but it was really just a way for Zeck to channel electricity into Slug's Namekian physique.
Unlike Tarble, who simply couldn't figure it out, Zeck had successfully learned how to convert his ki into electrical energy, based on the principles of Master Roshi's Electric Shock Surprise Attack.
The blast of pure electricity punched straight through Slug's ki aura and locked up the entire left side of the Namekian's upper body.
Zeck's second blow had much more power behind it. It was a proper jab from a fist wreathed in all of the electricity that Zeck's aura could muster.
Just the electric energy alone would be enough to slaughter an entire swamp full of alligators, and it ripped through Slug's aura like a hot knife through butter, directly into the muscle group that governed the Namekian's arm movement.
Slug's arm slammed into his own chest involuntarily with 'hysterical strength' levels of force. His arm muscles snapped, and his breastbone buckled for a moment. That was Zeck's 'Puppeteer Strike' technique. A technique that used the enemy's own body against itself.
Slug roared in pain, his foot lashing out on instinct in a ki-laced counterattack that lit up the sky and forced Zeck backwards in a dodge that had been forced slightly earlier than Zeck had anticipated. Slug's foot missed him by an inch, but the sheer force from the ki energy inside still cut a new seam into his shirt.
"Gah! What did you DO?!" Slug shouted, holding his arm, which hung limply at his side, still numbed from Zeck's first blow.
Zeck sweatdropped, knowing that the force from Slug's kick just then could very easily have cut him in half had he not dodged in time. "I thought you always regenerated?!" He taunted.
"..." The menacing expression on Slug's face grew several times darker. "You made a big mistake, young man… RAAAH!" He ripped his arm off at the shoulder without hesitation, then regenerated it a moment later.
Zeck smiled. The new arm hung limp, just as the old one had. The issue was with the nerves in the torso, not the arm itself. He'd just forced the Namekian to waste a nontrivial amount of power for no reason. The arm would likely only take a few seconds, maybe a minute or two, if the Celatian was lucky, to regain its function, but during that time, even regrowing the whole limb would be essentially pointless.
But in the next moment, the smirk slid right off of the warrior-scientist's face.
"RAAAAAHHHHHHH!" Realizing that his arm still didn't respond only served to deepen Slug's rage.
Bulma's voice, communicated to Zeck through the implant in his neck, rang in the back of Zeck's head in sequence with the waves of dark, suffocating power visibly rippling off of the Namekian. "ZECK YOU NEED TO GET OUT OF THERE! GO! RIGHT NOW! RUN!" She took a breath, "The analysis on his hidden power just came back!" She explained, "He's at twenty million, Zeck! You can't handle that kind of power! Get out of there-" With a mental command, Zeck shut the communication channel off, his mind already running calculations with Slug's new level in mind.
The first thing he did was power up to his full ten million power level. He could feel the strain on his body, but it felt like a nice, comfortable jacket against the suffocating evil that rolled off of his enemy, at the moment.
"YAAAAHHH!!!" With a final shout, Slug finished his powering up at the same time that Zeck did.
The Namekian was officially on a notably higher level than the Celatian. Zeck had lost his opportunity to flee, not that he'd actually had much of one to begin with.
Inwardly, Zeck sent out a prayer of thanks to his own foresight in ensuring that he had the ability to cut off the connection to Bulma's terminal from his end when he;d built the implant in his neck.
He didn't stop the flow of data. Bulma deserved to know what was going on, but, as much as he valued information and analysis, splitting his focus right now wasn't going to aid him in this fight, and hearing Bulma crying over the beating that he was about to take wasn't going to help, either.
But he still hadn't lost hope. If Slug's full power was only around twenty million, then the chance that the Namekian would actually manage to kill the Celatian was actually rather low. Zeck could win this battle… all he needed to do was pour every bit of focus into the fight in front of him.