Collateral damage is defined as any damage besides the intended target. This can range from civilians, buildings, and landscapes to entire solar systems full of innocent people not involved in a conflict. It's a very common visual tool to have, to have the viewer understand how big of a threat a force is, or to show a difference in power to the hero. In other cases, it just emphasizes the evil of the villain's villainy.
Across the anime/manga metaverse, there are many examples of characters that display a great deal of power and are literal forces of nature, but not many have actually displayed those abilities visually to the audience. Many anime have displays of collateral damage that are revolting paintings of destruction and carnage.
10 The Colossal Titan Destroyed The Wall (Attack on Titan)
Attack on Titan's Colossal Titan is truly menacing. From the first appearance of the large, massive 190-feet tall giant, viewers are introduced to pure chaos. One of the initial events in the series involves this Titan kicking down a section of the Wall Maria in Trost.
This attack led to a large number of casualties on its own, but what followed was bigger. Large groups of Titans poured into Trost and shut the entire section of the city off for years. This is visually one of the most destructive instances of a single creature destroying an entire city with a simple kick.
9 All For One Nearly Destroys A City (My Hero Academia)
As All Might's arch-nemesis and the first big threat in the My Hero Academia universe, All For One is a notorious force. A lot of All For One's power is never shown, but viewers are able to tell that he's physically on par with All Might.
During their final clash, fans can see countless buildings and a few city blocks topple over as the two fight. In My Hero Academia, so far, All Might's last fight is still one of the most destructive events to occur in the series that nearly left a city in ruins. Shockingly enough, it didn't seem like many civilians died in the battle at all.
8 Pain Destroys The Leaf Village (Naruto)
In Naruto's early days, one probably couldn't imagine a day where they'd see the entire Leaf Village destroyed, that is until Pain shows up. Pain is a member of the Akatsuki, a special group of rogue shinobi that have left their respective villages for one reason or the other. Pain is one of those shinobi and arguably one of the most powerful Akatsuki in the series.
Pain is the name given to 6 different individuals, all known as Paths. The Deva Path, in an attempt to lure out Naruto, destroys the entire Leaf Village with their Almighty Push ability. This ability allows Pain to manipulate gravity in a way that can deflect anything around them. This led to several deaths besides the initial assault by Pain and the entire destruction of the Leaf.
7 Ulquiorra Cipher's Attacks Are Nuclear (Bleach)
The 4th Espada of Aizen's Arrancar army, Ulquiorra displays some of the most destructive abilities in Bleach with his Lanza del Relampago attack. This attack is so powerful when launched that it causes explosions that dwarf Las Noches. Las Noches, for context, is large enough that it would take three days to walk around.
It's a big space and is at least the size of a large city based on that analysis alone. Ulquiorra can casually toss these around in his second form without too many breaks. Ulquiorra's fight with Ichigo also shows more destructive feats as large, thick building-sized pillars are destroyed by his one-sided beatdown of Ichigo.
6 Nappa Casually Levels Cities (Dragon ball Z)
During the Saiyan Invasion in Dragon Ball Z, Nappa levels an entire city with a simple gesture. No special ki-blast, just a single-hand motion. This is upon his arrival with Vegeta. The attack is so massive that it can be seen from space.
To add to that, later on, before the Goku encounter, Nappa runs off to terrorize another city as he takes on an entire army by himself, ripping through jets and destroying entire cities as he goes on a stroll through the nearby area as they wait for Goku to arrive. He returns with only a few scratches.
5 Akainu Destroys Half An Island (One Piece)
In One Piece, there's an island known as Punk Hazard, which is one-half ice and snow and one-half magma and fire. This was the aftermath of a fight between two Marine Admirals, Aokiji and Akainu. The half that was destroyed by Akainu has magma-like heat, lava flowing down the streets, and buildings melting as far as the eye can see.
The entire section of the island is constantly on fire and has been that way for years, the amount of damage done by the two has changed Punk Hazard's topography forever.
4 Lucy Destroyed An Island (Elfen Lied)
Lucy from Elfen Lied is a hard character to pin as a villain, but she certainly has the qualities of one. As a Diclonius, she's an evolved human with psychokinetic powers with the objective of bringing an end to the human race.
Lucy has many feats, from casually killing trained soldiers to wiping out large armies on her own. However, her greatest feat is when her psychokinetic arms stretched 1.25 miles into the air, sinking an entire island.
3 The Wretched Egg Destroys Japan (Deadman Wonderland)
The Wretched Egg from Deadman Wonderland is the most notorious figure in the series, who caused the Great Tokyo Earthquake. This attack destroyed about 70% of Tokyo. As a reference, 70% of Tokyo is 592 (591.5) squared miles, which is triple the size of Seoul, about double the size of New York, and almost as large as the Greater London Area.
This sort of event would be far above a 9.0 on the Ritcher scale. A 9.0 is like 20 trillion kilograms of dynamite going off.
2 Frieza Destroys Planets (Dragon ball Z)
At this point in Dragon Ball Z's history, planet-destroying seems pretty low-tier, but it's pretty uncommon for a character to do so and to do it successfully. The only times viewers have ever seen this done is by the almighty Lord Frieza. Frieza has destroyed the planet Vegeta, but also the planet Namek.
And considering weaker characters like Piccolo and Master Roshi were able to destroy the moon, this may as well have been a walk in the park for Frieza. The amount of damage from destroying an entire planet is hard to fathom, but that's how insane such a feat is for a character to pull off.
1 The Anti Spiral Destroys Galaxies (Tengen Toppa Gurren Lagann)
Whenever collateral damage is brought into the anime discussion, one series comes to most anime fans' minds and that is Simon versus the Anti-Spiral in Gurren Lagann. This battle involved two massive forces literally tossing galaxies at one another in the form of giant drills.
Dozens upon dozens of galaxies are flung around while these two powerhouses stand in the nothingness of space as if it was the ground below our feet. It is by far one of the most notable feats of collateral damage in all of anime history.