It's possible for the entire human race to be eliminated with a single blow. The scenario is scary to imagine, yet it's a common plot point that pops up time and again in anime. In particular, shonen anime frequently showcase their most epic villains' sick strength by having them kill millions of people with the wave of a finger.
Although the medium is known for featuring bright colors and cute characters, anime genocide is shockingly ubiquitous. To make matters worst, many of these atrocities occur as the result of a single attack, wherein countless lives are lost in the blink of an eye. After watching the world unceremoniously fall apart in The End of Evangelion, you'll probably want to go home and hug your loved ones.
Zenō may appear to be an adorable mascot, but he's actually the deadliest character to ever grace Dragon Ball Super. This king of the universe has the power to wipe out entire galaxies with nothing more than a thought.
To make matters worse, this Omni-King has a childish temper that matches his youthful appearance, which leads to him eliminating universes out of rage. The Dragon Ball canon once had 18 active universes, but Zeno erased six of them in a temper tantrum.
Out of all the Dragon Ball Z villains, Freiza is perhaps Goku's most memorable nemesis. His mere presence makes even the strongest DBZ fighters quake in their boots, and for good reason. At the time of his introduction, Freiza is the most powerful being in the galaxy, and is responsible for the destruction of Planet Vegeta.
Freiza destroyed the Saiyans' home planet out of fear that the legendary warriors would rise up and defeat him. Of course, DBZ fans know that despite Freiza's best efforts, that prophecy comes true in the form of Super Saiyan Goku.
Civilians and soldiers alike are massacred in the beginning of Attack on Titan; the slaughter begins with the fall of Wall Maria. Thousands of city residents are killed in the attack, and 250,000 soldiers are sent off to die in a failed counterattack.
The horrific event perfectly establishes the stakes for the adventure, as it demonstrates the raw, destructive power of the Titans.
While the original Fullmetal Alchemist series features Dante as the final villain, the 2009 series FMA: Brotherhood sticks more closely to the manga and introduces Father, one of the smartest anime villains of all time. Father is birthed from the blood of the powerful alchemist Van Hohenheim, who is later manipulated by Father to bring about the destruction of the Xerxes Civilization.
Father uses the lost souls of the Xerxes Civilization to transform himself into a living philosopher's stone that resembles his human puppet Hohenheim.