When Piccolo first made his introduction back in Dragon Ball, no one would've ever expected that he'd turn out to be one of the good guys. Despite being the son of the evil King Piccolo, it didn't take much for him to side with Goku to defend the planet from the Saiyans. After that, Piccolo embraced his role as one of Earth's mightiest defenders, standing alongside Goku throughout some of his toughest fights over the years.
While it's usually a Saiyan warrior that gets the last strike on an enemy, Piccolo's racked up his fair share of kills over the years as well, proving that no matter how virtuous he's become, he still won't hesitate to obliterate anyone who threatens the safety of his home, his friends, and more importantly, Gohan.
9 Goku & Raditz
Piccolo developed his infamous Makankosappo for the sole purpose of killing Goku, but it was too slow for him to actually hit anyone with. During the fight against Raditz, Goku was forced to restrain his older brother, leading to both of them being impaled by such a powerful attack.
After killing Goku, Piccolo had successfully accomplished the goal that he (and so many other Dragon Ball villains) had always been set on doing, although the threat of Nappa and Vegeta's arrival soured what celebration he could've potentially had.
8 The Last Saibaman
Krillin managed to defeat most of the Saibamen with his Scatter Kamehameha; only one managed to avoid such a deadly move. It attacked Gohan, but before it could harm him, Piccolo rushed to Gohan's defense, tossing the Saibaman into the air and obliterating it with a powerful blast from his mouth.
Not only did this show just how attached Piccolo had gotten to Gohan, but it also showed just how powerful Piccolo had become. It took someone like Yamcha, who'd also spent the last year training, a fair amount of effort before he was even able to down a Saibaman.
7 Sansho
Most of Piccolo's kills occurred across Dragon Ball Z's many movies, not only showing a darker side to his personality that was lost as the years went on, but also his commitment to defending Earth. In the beginning of the first Dragon Ball Z movie, Dead Zone, he was ambushed by Garlic Jr.'s top henchmen, Ginger, Nicky, and Sansho, making viewers believe that these warriors were actually a threat.
Later on, he and Sansho fought one-on-one, proving otherwise. It looked like Piccolo was barely even trying when they fought, since Sansho wasn't anything to write home about on his own. In the end, a simple ki blast was enough to get the job done.
6 One Of Dr. Wheelo's Bio-Men
Dr. Wheelo possessed some truly strange henchmen, but by far the most peculiar were his Bio-Men.
Their design brought back memories of the Saibamen, with the animators including a clear throwback to the Saiyan Saga with the manner in which Piccolo killed one of the Bio-Men in a near-identical manner as he did with the Saibaman, throwing his opponent into the air and obliterating it with a ki attack from his mouth.
5 Some Of Slug's Footsoldiers
With Goku and Krillin nowhere to be found, Gohan took it upon himself to defend Earth against Lord Slug's forces at the start of the Dragon Ball Z movie Lord Slug. While he put up a good fight, he was eventually outnumbered and overwhelmed.
When all looked hopeless for him, Piccolo arrived at the last second to save Gohan from certain death, taking many of Lord Slug's foot soldiers out himself before being separated from Gohan by one of Lord Slug's stronger subordinates.
4 Wings
While Lord Slug possessed several dozen soldiers at his disposal, he wouldn't have been able to get very far without the assistance of three exceptionally powerful henchmen, with one being Wings. While Wings' size makes him look intimidating, he actually didn't amount to very much, lasting only a few short minutes against Piccolo and failing to deal any damage to him at all.
Piccolo saw through all of his attacks, and even crushed his fist at one point. After knocking Wings to the ground, he pretended to side with him for a brief moment before decapitating him with a ki blast at point-blank range, ensuring that Wings' death was equal parts cold-blooded as it was painful.
3 Every Member Of Cooler's Armored Squadron
Cooler's Armored Squadron, though not as big as the Frieza's Ginyu Force, were just as powerful, with their own unique abilities that enabled them to dominate almost any opponent that stepped up to face them. The first to go was Dore, the squad's resident muscleman, who was vaporized by a powerful homing ki blast from Piccolo. Neiz was next to go after he used an electrical attack called the Neiz Bind Wave (a move strikingly similar to Master Roshi's Thunder Shock Surprise).
At first glance it looked like this attack had stopped Piccolo, but when Neiz got close, Piccolo latched onto him, reflecting the attack and causing Neiz to be fried by his own technique. He and Salza had a fierce battle of their own, which Piccolo had the upper hand in until Cooler showed up and ambushed the Namekian. Viewers were led to believe that he was down for the count after that, but when Salza emerged as the last man standing shortly after Cooler was hurled into the sun, Piccolo's Makankosappo took him out from afar.
2 Several Cyclopian Guards
It might be a stretch to even count the Cyclopian Guards that assisted Meta-Cooler during his attack of New Namek as alive, given that they were actually robots created by the Big Gete Star. Yet it wouldn't be a stretch to say that Piccolo took down several of them on his own, coming up with the strategy of concentrating all of his energy to break through their firm metal plating at the moment of attack.
Despite being horrendously outnumbered, he took down most of these robots with a huge explosive wave, creating an enormous crater on his homeworld as an added bonus.
1 Hatchiyack
Most of Piccolo's kills occurred due to his powerful energy attacks that, while they weren't always the flashiest, often got the job done without wasting too much time. Unlike some of his allies, he tends to forgo mercy, and kills his opponents because he realizes that their deaths are necessary.
While most of his kills are done without the help of others, the fight against Hatchiyack was one that no Super Saiyan or Super Namek could win alone. In the end, he combined his Makankosappo with the ultimate attacks of Goku, Vegeta, Gohan, and Future Trunks to create a blast so powerful that even Hatchiyack couldn't hold it back.