Guys, in all reality, neither is a very good bad guy in comparison to others. Niju was just an misunderstood ugly-face who was afraid of change. Steele was a brute, womanizer, and unintentionally put kids' lives at risk. The latter wasn't Steele's goal. His goal was to show he was better than Balto. Big whoop. I can think of 20 other bad guys (in animated features) and why they're worse than Mark Hamill trying to make a quick buck, and the wolfaboo's idea of a cyber bully.
Now, my list does not include villains who have left a pretty huge scar and frightened the total crap out of me. This is mostly based on what they've done and to the degree of what they've done.
1) Name: Mewtwo
Featured in: Pokemon: The First Movie
Description: A man-made clone of a creature named Mew, made specifically for it's power and destruction.
How they were wronged: No one respected that he wanted to find his true reason for being, used him to fight their battles.
Crime(s): Telepathically created a world-wide storm, created more clones like himself, destroyed entire islands and buildings, and aside from that killed hundreds of humans and Pokemon, and that was just the beginning for him.
2) Name: Judge Claud Frollo
Featured in: The Hunchback of Notre Dame
Description: An old judge blinded by his self-righteousness.
How they were wronged: Eh.... he wasn't really wronged xD
Crime(s): Setting all of Paris on fire to capture the reason behind his uncontrollable lust and mentally disfiguring a deformed child all the way to adulthood.
3) Name: Tai Lung
Featured in: Kung Fu Panda
Description: A giant snow leopard master of various types of Kung Fu.
How they were wronged: They were vigorously trained and led on to being the ultimate legendary Dragon Warrior.
Crime(s): Vengeful destruction on the entire Valley of Peace, using only his bare hands and feet.
4) Name: Lord Shen
Featured in: Kung Fu Panda 2
Description: A sickly albino peacock, heir to the peacock clan.
How they were wronged: Being banished for trying to change his fate in the only way he saw fit.
Crime(s): Exterminating many animals and near-all of the panda population using fireworks as a weapon.
5) Name: Zira
Featured in: Lion King 2: Simba's Pride
Description: A lioness follower and possible suitor to the dead King Scar.
How they were wronged: Exiled for her political viewpoints.
Crime(s): Mutiny, indirectly causing the death of one of her children, brainwashing and brutally training her son to murder the king, and otherwise being a bad mom.
6) Name: Lady Tremaine
Featured in: Disney's Cinderella
Description: A vile looking old woman with a permanent sneer on her face.
How they were wronged: Having bad genes.
Crime(s): Married a nobleman and supposedly killed him. Took over his land, and afterward abused and humiliated her step-daughter and forcing her to become a servant in her own estate.
7) Name: The Queen
Featured in: Disney's Snow White and the Seven Dwarfs
Description: An evil-looking queen lol
How they were wronged: Despite anything she's done in her life, good or otherwise, she's overlooked by a mere child.
Crime(s): Hiring a hitman to kill an eleven year old girl and bring her back her heart. Changing her identity and afterward poisoning her. And that's just the movie, you haven't even read what she's done in the book LOL It's four accounts of attempt at murder.

Name: Nightmare Moon
Featured in: My Little Pony: Friendship is Magic
Description: A giant black alicorn (unicorn/pegasus mix) with reptilian eyes, and a mane and tail made up of stars
How they were wronged: Her people didn't appreciate her bringing the night and her sister failed to see her side of the story.
Crime(s): Bringing fourth eternal night, which would lead to plants dying and therefore starving the entire population.
9) Name: Pascal
Featured in: Felidae
Description: A elderly mistreated cat.
How they were wronged: Abused and experimented on for most of his life.
Crime(s): Creating an entire religion among cats dedicated to his cause, of breeding cats back to their origins and going so far as to murdering cats and humans alike to get what he wants.
10) Name: Discord
Featured in: My Little Pony: Friendship is Magic
Description: A draconequis, otherwise a chimera with a head of a pony and a disproportionate body made up of other animals.
How they were wronged: Being encased in stone for keeping things in balance by being the embodiment of chaos itself.
Crime(s): Turning the entire world haywire in the most unlivable way possible.
11) Name: Marceline's Dad
Featured in: Adventure Time
Description: A blue-skinned, dark haired, vampire wearing a suit. His other form is an indescribable cluster of teeth, mouths, organs, sacks, and who knows what else.
How they were wronged: Nothing's really known about him xD But he's evil.
Crime(s): His smallest offense was eating his daughter's fries. His second smallest offense was sucking out all the souls of Ooo.
12) Name: The Joker
Featured in: Batman... everything
Description: You don't know the Joker? Go away.
How they were wronged: No one knows.
Crime(s): Kills people, namely in "comedic" ways. Blows stuff up. Just creating chaos for everybody in every way possible. All because he knows that no matter what he does, he's just gonna to go Arkham, just to get out again.
13) Name: Queen Beryl
Featured in: Sailor Moon
Description: A pale-skinned seductive woman with red hair and a dark dress, and sharp fangs.
How they were wronged: Hmmm...
Crime(s): Aside from her longing to take over the universe and destroying humans and her enemies, the basics. She's disposed of more henchmen than any other listed villain, or probably any villain ever. Is he because she's weak? Of course not. So why would she get so many of her followers killed off? Evil.
14) Name: Poison Ivy
Featured in: Batman
Description: Red hair is her best known feature, but often times she's seen with either green or pale skin. She's usually seen in a leotard, but is more comfortable in nothing.
How they were wronged: Well, circumstances led to her mutations and her immunity to all poisons and toxins. But people keep killing her children (her plants).
Crime(s): Her disregard for human and animal life surpasses that of Cruella DeVille, but this is a woman so powerful, she can do everything about it. S one of the world’s most prominent eco-terrorists. She uses toxins from plants and mind controlling pheromones for her criminal activities, which are usually aimed at protecting the natural environment.
15) Name: The Coachman
Featured in: Disney's Pinnochio
Description: A fat sinister, red-faced man who runs Pleasure Island, especially behind the scenes.
How they were wronged: Nothing is known about him.
Crime(s): Poses an amusement park as a safe haven for boys, allowing them to drink, smoke, gamble, whatever they want. Then turns around and kidnaps them and somehow turns them into squawking donkeys. No one knows what he does to the boys who still talk. And his fate is left unknown. He probably still did it long after the movie's events.
16) Name: Akito Souma
Featured in: Fruits Basket
Description: A sickly androgynous young man?
How they were wronged: They were born and told their purpose is to die, and that everyone is going to leave.
Crime(s): Mentally abusing every member of the Souma family into submission and chronic depression and self doubt, especially knowing that he's the one that they're cursed to love and worship him no matter what he does. Sure, he doesn't have long to live, but he's not going to let anyone be happy.
17) Name: Rei Ayanami
Featured in: Neon Genesis Evangelion
Description: A soulless... pale... red-eyed young woman...
How they were wronged: ....she exists......
Crime(s): God, I can't even.... too horrible.
18) Name: Love Machine
Featured in: Summer Wars
Description: Godlike in appearance and in action. He is an AI (Artificial Intelligent) program created by Wabisuke Jinnouchi.
How they were wronged: It was created by man.
Crime(s): It's a virus, basically. A gigantic virus. And a powerful one at that. Since nowadays and in the future, everything is run digitally. Computers, cell phones, operating equipment, airlines, transportation, hospitals, communication, entertainment, electricity, everything is run digitally. So what does it do? It hacks into all of it in a matter of seconds, makes everything malfunction, including electricity to run our lights, our water, and that doesn't exclude launching every missile digitally and electronically available. Chaos beyond chaos, and all of it estimated to happen within 2 hours and ten minutes. Behold the idea of our generation's ultimate evil.
19) Name: Johan Liebert
Featured in: Monster
Description: Your typical German boy, blue eyes, blonde hair, composed posture.
How they were wronged: He says he was born this way. But it didn't help that his twin sister shot him in the head as children and he was sent to Kinderheim 511 where he was experimented on to be turned into the "perfect soldier".
Crime(s): Johan is a sociopath. He has no conscience, whatsoever, and revels in human suffering. He is incredibly persuasive, even when he's done nothing to earn trust. He once got 50 men to kill each other over something incredibly little. But I don't think any of that is worse than convincing a child to... I can't even say it here xD
20) Name: Life
Featured in: It's in every good movie actually.
Description: It just life.
How they were wronged: It happens.
Crime(s): Some of the best movies don't even have villains. It's just life happening to them, and life going wrong, and life going right all at once. It doesn't have a face or identity, and is seen as both wonderful and terrible. It's something we're given by chance or by fate, and characters experience it as people experience it. Some characters have to battle nature, some themselves, and some deeeeeep within their own mind. Some prime examples of life happening is: Lilo and Stitch, The Land Before Time, Bambi, An American Tail, and many others. Those movies don't have villains. Sure, they have villainous characters, but they aren't the main focus or main problem in them, and the protagonists have much bigger things to worry about.
So I cheated on the last one, but hey. ALL of these stump Steele AND Niju combined in "evilness."