The smash-hit anime My Hero Academia not only has a diverse cast of heroes and student heroes (from Shoto Todoroki to Tsuyu to Mineta), but also a variety of chilling villains. After all, how else to test a hero's mettle than a powerful villain to fight? Villains use their powers for selfish and destructive acts, and a villain's ideology and a hero's are almost never compatible.
Two particular villains stand out in My Hero Academia. First, we meet Stain, a sort of blood-based ninja who's determined to weed out "phony" superheroes. Later, the terrifying All For One takes center stage, who is arguably the boss villain. Which one should be considered the better villain overall? Each bad guy has some merits, after all.
10 Stain: A Rogue
Being a rogue does not mean being evil, but Stain certainly is both. A rogue is not bound to a cause or an organization, instead roaming and operating independently for their own ideologies and reasons. Rogues can be fun since they're unpredictable, and they have total freedom that a viewer might (deep down) envy. Stain is a one man army, and who knows where or when he'll strike? He has no allies, friends, or family to use against him, either. Catch him if you can!
9 All For One: Multiple Quirks
Some characters in fiction have a wide variety of abilities, and some of them might even be stolen. In Bleach, the villain Aaroniero has eaten many hollows to gain all their powers, but he was slain all the same. All For One takes this concept even further, using his base quirk to steal many others! He has dozens in that arsenal of his, and many can be used together to form a unique (and devastating) effect. That's how he can stand up to even All Might and keep fighting.
8 Stain: Cool Costume
What's a hero or a villain without a cool costume to call their own? Rarely do such characters wear uniforms, but, instead, create an outfit that makes them stand out. These costumes are often a reflection of the character's abilities, personality, and more. All of the UA students are asked to design their own costumes, and Stain has his own scary wardrobe, too. It's practical but stylish, with flowing and ragged scarves, combat boots, ninja gear, and knives and swords to make his quirk easier to use.
7 All For One: Dressed To The Nines
Stain's costume is unique and cool, but All For One is a visual to never forget. Of all things, he wears a gentleman's suit into combat, and a suit isn't normally what you wear into battle. This makes All For One look professional, confident, and stylish, and the ordinary suit contrasts sharply with his scary mask. It's been suggested that All For One's helmet is inspired by Darth Vader, and he'd look pretty ordinary without it. Suit up!
6 Stain: Ideology
A good villain needs a proper motivation. Some are somewhat sympathetic, such as getting revenge against a cruel world for the death of a loved one. Other villains act because they want to reshape the world, and Stain is like that, too. He can't tolerate heroes acting for fame and money, seeing them as fakes who must be culled.
To that end, he took it upon himself to hunt them down and even kill them! Stain sees All Might and later Izuku in a different light, considering them legitimate heroes. This gives Stain some depth beyond "he wants to kill people."
5 All For One: History With All Might
Part of what makes All For One so scary is that he is in fact quite old and has a history with the hero world. He's been gathering quirks for decades, if not a full century, and he's clashed with many heroes since then. Most prominently, All For One once dueled All Might, and the latter has the scars to show it. When these two fight once again, it's thrilling (and scary) since All Might is facing the man he couldn't defeat earlier. So, how is he supposed to do it this time?
4 Stain: A Bloody-good Quirk
Just what can Stain do? He's not assassinating all those pro heroes by poisoning their food. Rather, his quirk is called Bloodcurdle, and it's really something. Once Stain cuts a hero and ingests their blood, he can paralyze them, and they are helpless before him.
We see this vicious quirk in action against Tenya Iida, Shoto Todoroki, and even Izuku Midoriya. Fortunately, this quirk doesn't last as long against some blood types, so some heroes can break free of its effects sooner. But, until then, watch out!
3 All For One: A Way With Words
All For One is a scary villain who is memorable not just for his devastating combat abilities, but for his mental warfare, too. Even after this monster was captured and detained in Tartarus, his words cut deep into All Might's soul when they came face to face.
All For One taunted him, saying that with All Might retired, the way is clear for more and more villains to rampage across society. Not even the UA students may be safe, and evil will never die, even if All For One is in prison like this.
2 Stain: Mystery Man
Stain is a man who appeared out of the shadows without warning, and that makes him all the scarier for it. His real name has been discovered, but not much of his origins. Did he attend UA or a similar school, or is he a self-taught fighter? Did he grow up in an abusive household, or did he reject a warm family life to pursue his mission? He's only been seen on the battlefield, so it's difficult to figure out the man behind the monster. Spooky!
1 All For One: He's A Leader
It's cool to watch Stain operate independently as a villainous rogue, to be sure, but All For One is a potent foe since he's not alone. This terrifying man is a leader and inspiration to many villains, combining them into a cohesive fighting force that gives the heroes a real challenge, to say the least. Much like All Might, All For One is grooming his heir; in this case, Tomura Shigaraki. Evil will never die as long as All For One has minions who believe in his cause.