There are many admirable qualities in anime heroes: they're often determined, fierce, loyal, protective, and never give up. They love and cherish those closest to them and have a strong sense of right and wrong. They may not be completely perfect, but they're perfect fits for their stories.
Villains, meanwhile, are characters who help drive a story along by giving these heroes someone to overcome. Characters can become villains for various reasons, some good and some bad, and they have some great and terrible qualities of their own. Goku of Dragon Ball fame is a not-so-perfect hero who's been able to convert many one-time villains into allies, and he'd be able to do the same with numerous compelling villains across anime series.
10 Nagato Made Bad Choices For The Sake Of Peace And Prosperity (Naruto Shippuden)
Nagato, along with his two best friends, were war orphans who wanted to bring peace and prosperity to all the nations. However, when his friend Yahiko died, Nagato adopted the identity of "Pain" and led the Akatsuki to bring peace to the world in any way possible.
He's the type of person that Goku would be able to relate to, sharing his dark past and the history of his people. Goku would be able to convince Nagato to find a better way to bring about peace, much like Naruto did.
9 Gajeel Redfox Is Tough On The Outside But Soft On The Inside (Fairy Tail)
Gajeel Redfox is a tough-as-nails Iron Dragon Slayer and was a member of one of the darkest and strongest guilds in Earth Land: the Phantom Lord guild. Gajeel was cold and indifferent, and he didn’t care who he hurt with his actions.
On the inside, though, he's emotionally vulnerable. This is something that Goku would be able to connect with, as they’re both tough guys and who feel a duty to the people that they're bound too. But much like Natsu did, Goku would be able to get Gajeel on his side.
8 Crona Had No Choice In Their Evil Upbringing But Can Change Their Future (Soul Eater)
Crona, or the Demon Sword, as they're more commonly known, is a demon sword master and the child of Medusa Gorgon. Unfortunately for Crona, they didn't get a choice in being anything other than bad. With someone as sadistic as Medusa for a mother, Crona quickly learned they had to do whatever she said or suffer horrific consequences.
Having a family that malevolent is something that Goku would be able to relate to Crona about. He would also encourage Crona to be their own person on the side of good, like they've always wanted to be.
7 Nico Robin Had A Difficult Past But Has Many Redeemable Qualities (One Piece)
Nico Robin, or the Devil Child as she's sometimes known, and was one of the antagonists in One Piece. She even served Crocodile, an ex-Warlord. She was also physically and verbally abused by her family when she was a young child and was often told that she wasn't wanted.
With their similarly lonely pasts and experiences with people who wanted to use them and mistreated them for their own person gains, Goku would be able to connect with Nico on a deep level and convince her to be his ally.
6 Scar Seeks Revenge For His Family And Shares Many Of Goku's Best Qualities (Fullmetal Alchemist: Brotherhood)
Scar is a nameless vigilante who targets the State Alchemists as a form of revenge for the slaughter of the Ishvalan people, including his own family. He uses an alchemical tattoo that belonged to his older brother to take down his foes. He's also incredibly talented at hand-to-hand combat and can analyze situations on the fly.
With their love of fighting, tragic backgrounds, and shared need to protect and seek vengeance, Goku would be one of the few people who could connect with Scar and get him to become an ally.
5 Seto Kaiba Grew Up Mostly Alone And Became Selfish And Arrogant (Yu-Gi-Oh!)
Seto Kaiba is one of the antagonists in Yu-Gi-Oh! He's a ridiculously rich kid who's willing to do whatever it takes to collect — or destroy — rare Duel Monster cards. Estranged from his family, he was often alone and became selfish and arrogant as a result.
With a similar background, where he was separated from his parents and adopted by Grandpa Gohan, Goku would be able to understand what Kaiba was going through and help him become a better person. Through this, Goku would be able to convince Kaiba to become an ally.
4 Patolli Cares For Those He Holds Dear And Protects Those Who Are Loyal To Him (Black Clover)
Patolli, or Patry as he’s known in the English dub version of Black Clover, is an elf and the leader of the Eye of the Midnight Sun, a group of rogue mages who wished to destroy the Clover Kingdom. He loves those who are loyal to them and would do anything to secure their safety.
Much like Patolli, Goku is strong, and they have very similar moral codes, namely that they would do anything for those they care about. Goku would find a way to show Patolli a new and better path and would make an ally of the strong elf.
3 Sakura Inami Has Suffered A Great Deal But Knows How To Adapt And Change (Beyond The Boundary)
Sakura Inami is one of the primary characters in Beyond The Boundary, an anime about Spirit World Warriors and youmu. Sakura is careless, pigheaded, strong-willed, and ready to do anything necessary to get revenge for the death of her older sister.
Similar to Goku, she has suffered a great deal in her life, and does care for those who she holds dear. She also knows when to let go and pursue a new path, making her someone that Goku would be able to convince to join him as an ally.
2 Bakugo Katsuki Is Hot-Headed But Has Many Noble Qualities (My Hero Academia)
Bakugo Katsuki is a top-ranked student at U.A. High School and is training to become a Pro Hero. He's very temperamental, short-sighted, aggressive, and crude, all of which are traits that don't make a very good hero.
But he's also strong and straightforward, and he shares a number of good qualities with Goku. The two would definitely get along, and it'd take someone like Goku to help Bakugo let go of some of his worse traits to become a welcome ally.
1 Viral Has The Fighting Spirit Of A Saiyan (Gurren Lagann)
Viral was one of the first antagonists in Gurren Lagann. He's cocky, headstrong, and often calls humans naked apes. He's also a proud warrior who loves battle and despises dishonorable tactics or underhanded methods of fighting.
In many ways, he's similar to the Saiyans, who also love to fight above all else. Much like how Goku and Vegeta went from being enemies to friends, Goku and Viral would be able to connect on the same level and become allies in no time.