All villains, regardless of genre or media, need to have some sort of Achilles Heel. Otherwise, they run the risk of being way too strong for the protagonists to take down realistically. The solution to this can be unorthodox or comical, as many anime protagonists have gotten away with using some of the strangest methods for defeating their most threatening enemies.

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Sometimes this works out well within the story, but other times it's a little over-the-top. Though ultimately, a villain's silly weakness can add something fun and interesting to the plot, and it might even improve that character's likability as a whole.

10 A Monster Raven Cannot Handle A Duck Dancing (Princess Tutu)

Princess Tutu Duck As A Duck Dancing

Considering all of Princess Tutu is about a magical fairy tale world mixed with classical dance, it makes sense that a lot of Duck's problems are solved when she transforms into Princess Tutu and dances to thematic classical music.

Eventually, Duck and her friends make their way to the final showdown with the Raven, and she loses her magical amulet which allows her to turn into a human girl and then into Princess Tutu. So she, as a duck, proceeds to dance in order to rally her friends together and defeat the Raven.

9 The Homunculi Are Weak To Themselves (Fullmetal Alchemist)

Fullmetal Alchemist Broken Mirror Homunculus Ed

In the original Fullmetal Alchemist anime adaption, the Homunculi were even weirder and harder to understand than in any other incarnation of them. Any contact with something of their former self would render them completely useless, making for some easy tricks from the State Alchemists to destroy the lot of them.

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However, it wasn't limited to large pieces of their former human selves. Instead, it could even be something as small and inconveniently simple as a hair.

8 Aaroniero Arruruerie Loses Everything To Artificial Sunlight (Bleach)

Aaroniero Arruruerie Taking On Kaien Shiba's Form

Aaroniero Arruruerie is a massive powerhouse in Bleach and one of the strongest Espada warriors out there, but he's really weak to sunlight. This includes fake sunlight, as evident in the battle with Rukia where she breaks open the ceiling and changes the course of the fight.

While it doesn't actually kill him, it does render his shapeshifting abilities useless. It is an odd weakness, considering Aaroniero had recently been stationed there in a castle with fake sunlight.

7 Lord Slug Hates Whistling (Dragon Ball Z: Lord Slug)

Dragon Ball Z Lord Slug covering ears

While the Dragon Ball franchise is filled with very unusual villains with their own weird little quirks, Lord Slug takes it a step further in the Dragon Ball Z: Lord Slug movie. He lets the evil in his heart take over and transform him into the rare and powerful Super Namekian that he is. His real downfall is that he hates whistling so much, to the point where he even banned it from his presence altogether.

6 Kaguya Otsutsuki Is Stunned By Naruto's Reverse Harem Jutsu (Naruto: Shippuden)

Kaguya Sparkling Shocked Naruto

There are plenty of ways in which the ultra-powerful Kaguya Otsutsuki should not have been defeated by Naruto and the gang. However, in true Naruto fashion, the protagonists were going to press on regardless of how improbable it was going to be.

The good news was that one of Naruto's most iconic and gimmicky jutsu got to be used again, and even his friends couldn't believe that the distraction of a bunch of naked men was enough to give them the edge in battle.

5 Kurogiri Wears A Neck Brace To Protect His Weak Point (My Hero Academia)

Kurogiri League Of Villains Powers My Hero Academia

Kurogiri of My Hero Academia can hide his physical form and change his shade shape however he wants, but his neck brace draws a lot of attention to his weak point.

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Without a glaring point like that neck brace to target, he probably would have been too much for anyone to handle. It even gives away the fact he has a physical form at all and ends up being the catalyst for his defeat.

4 D'Arby Doesn't Cheat (JoJo's Bizarre Adventure)

Terence D'Arby holds Kakyoin's soul doll - JoJo's Bizarre Adventure: Stardust Crusaders, Battle in Egypt

JoJo's Bizarre Adventure is meant to be full of the weirdest possible things and characters with the weirdest quirks in anime. D'Arby was no exception and would steal the souls of those who lost to him in a video game. However, it apparently never occurred to him to cheat himself.

Therefore, it was actually pretty easy to beat him with the same dirty tricks that he should have been using all along as a villain. Instead, he really freaked out when he was beaten because someone else had the audacity to cheat.

3 Perona Is Horrified Of Cockroaches Despite Being A Ghost (One Piece)

One Piece Perona crying from cockroaches

One Piece is another anime full of the weirdest, most bizarre settings and characters. Perona was no exception, but her extreme aversion to cockroaches was a little weird considering she was a ghost. It was such a big deal that a ball of fake roaches was enough to get herself tangled into her own traps. It made for a pretty easy solution to all of the trouble she was causing.

2 Colonel Vulcan Can't Have Fire On Him Despite His High-Tech Suit (Promare)

Promare Colonel Vulcan smiling

Colonel Vulcan spends the entire Promare movie as head of Freeze Force in a full mech suit that makes him appear larger and more intimidating than he is. For a guy who constantly fights fires and throws his weight around for an excuse to capture innocent Burnish, it's surprising that fire is his true weakness. He should really be prepared to be covered in fire, especially considering he has all that modern tech he's so proud of.

However, after Galo De Lion covers the world in a protective teal fire, Colonel Vulcan ejects himself from his mech and immediately starts rolling around and panicking about being on fire, despite the fact that it doesn't hurt.

1 Hisoka Has Extremely Volatile Emotions That Get Him Into Trouble (Hunter X Hunter)

Hisoka close up in Hunter x Hunter

Fan-favorite Hisoka from the remarkable Hunter x Hunter is an unpredictable hunter who never fully gets destroyed, and it's not clear where he stands with the other characters.

The thing is, he easily gets caught up in the present and his current feelings. He manages to take care of himself for the most part due to his extreme skill and unique Nen, but acting on his emotions has caused some serious damage before. If he gets too excited about something, it can really sway whose side he's on and get him into some serious trouble.

NEXT: 10 Anime Villains Who Never Get Their Own Hands Dirty