The iconic Z-Fighter, Piccolo, was originally a bloodthirsty villain of horrific proportions within Dragon Ball continuity, and the world may have been better off if he stayed that way as Piccolo proved to be even more ruthless as a hero than he ever was as a villain.
Piccolo was introduced into the world of Dragon Ball as the Demon King Piccolo–a centuries-old villain who was trapped in a mystical vessel through the Evil Containment Wave many years before his manga debut, and was awakened to once again throw the world into chaos. After King Piccolo briefly conquered the planet, Goku was able to defeat him by flying through his torso, leaving behind a gaping hole that killed him in a matter of minutes. Before he died, however, King Piccolo produced an egg containing his own reincarnated form–the Piccolo fans know and love today. While ‘Piccolo Jr.’ initially sought to follow in his ‘father’s’ villainous footsteps, he quickly joined forces with the Z-Fighters and became a hero–and in one saga, that decision resulted in the deaths of millions.
In Dragon Ball chapter 487 by Akira Toriyama, Majin Buu arrives at Kami's Lookout unexpectedly after leveling up to a much more powerful form. At this point in the series, Goku and Vegeta are dead and Gohan is presumed dead, so the only ones left on Earth strong enough to fight Buu are Goten and Trunks. The only caveat is, the two half-Saiyan children would only be powerful enough to stop Buu if they achieved perfect fusion, otherwise they wouldn’t stand a chance. So, to give Goten and Trunks more time to train inside the Hyperbolic Time Chamber, Piccolo suggests the unthinkable to Majin Buu.
Piccolo Encouraged Majin Buu to Kill Millions of People
To give Goten and Trunks as much time as they needed to train, Piccolo suggests that Buu kill every person on the face of the planet and then come back when he’s done. Before Buu arrived at the Lookout–when he was still flying around with Babidi–Buu stated that he was going to kill everyone on Earth, so Piccolo used that to his advantage in this situation. Unfortunately, Buu was much stronger than Piccolo gave him credit for–so while Buu followed Piccolo’s suggestion, he was able to kill everyone on Earth in a matter of seconds with a single blast, all without having to leave the Watchtower. Just like that, Piccolo became responsible for mass genocide on a planetary scale.
Back in the original Dragon Ball manga when King Piccolo took over the world, all he did was destroy a few cities and incite violence. While that was pretty bad, it at least allowed humanity a fighting chance instead of simply condemning them all to a swift death by the hand of Majin Buu just to give Dragon Ball’s heroes a bit more time to train–proving that Piccolo is more ruthless as a hero than he was as a villain.