From Vegeta to Joey Wheeler to Sasuke Uchiha, anime is full of deuteragonists that fans cannot seem to get enough of. Sometimes, they get plenty more than the main protagonists do!
This list will chronicle the anime where deuteragonists like Homura from Madoka Magica break the mold and are better handled and developed than the main characters themselves.
Note: No ensemble casts (so no RWBY, Sailor Moon, or team-based shows)
Note 2: This article is the author's opinion only, and will contain spoilers for all anime listed.
10 anime where the deuteragonist is better developed than the protagonist
These are 10 anime where the deuteragonist is better developed than the main character.
1) Dragon Ball Super (and Z to a lesser extent)
The deuteragonist(s) of Dragon Ball Z and Super tend to be better developed than main protagonist Goku. To clarify, it's Vegeta, Gohan, and Piccolo who mostly develop as characters.
Gohan goes from being Goku's scared kid, unable to fight except in times of extreme anger, to being a better father to Pan and a confident fighter. Piccolo went from wanting to kill Goku to being Gohan's reluctant teacher to sacrificing himself for Gohan multiple times.
Vegeta has had the most development, going from the arrogant and narcissistic "Prince of All Saiyans" obsessed with surpassing Goku to forsaking training to be with Bulma during Bulla's birth! Vegeta has become a much better person overall throughout Dragon Ball Z and Super thanks to his family.
Goku, on the other hand, while gaining power exponentially, has seemingly backslid as a character. Despite loving his family, he foresakes them for training. His godly power appears to have addled his brain somewhat, leading him to make many dumb decisions.
2) JoJo's Bizarre Adventure: Diamond is Unbreakable
The entirety of JoJo's Bizarre Adventure, Diamond is Unbreakable features the deuteragonists developing more than the main protagonist.
The main deuteragonist, Koichi Hirose, is the perfect example. Koichi went from being a kid uncomprehending of Stands to an instrumental cast member via his Stand ECHOES. Likewise, he became smart and clever enough to stop several villains on his own and tracked the serial killer Yoshikage Kira alongside Jotaro Kujo. Koichi landed one of the final blows in the team attack against Kira, weighing his hand down with Echoes ACT 3 to prevent him from escaping via a remotely trigged bomb.
Secondary deuteragonist Okuyasu Nijimura tried to kill main protagonist Josuke Higashikata. Following his brother's death at the hands of the Stand Red Hot Chili Pepper, Okuyasu joined Josuke to find the killer. Okuyasu becomes a genuine friend and less of a delinquent as the series progresses.
Josuke himself was out of focus for most of the series, but still became less of a punk as time went on.
3) Puella Magi Madoka Magica
Madoka herself goes from normal to magical girl to goddess. Homura, on the other hand, has gone from a magical girl to a time breaker who wants nothing more than to be with Madoka. She's so desperate to have Madoka for herself that she damns everyone else by shattering Madoka's "Good Ending" timeline in the Rebellion movie, undoing all of the positive changes and nearly destroying the universe.
Yugi's friends, especially the deuteragonist Joey Wheeler, develop more than Yugi himself.
Joey Wheeler started out as a lowlife punk who only cared about his sister, Serenity, and bullied Yugi, throwing a piece of the Millennium Puzzle into the school pool as one of the first big bullying acts. Yugi stood up for him against a larger bully, causing Joey to reassess Yugi and get that piece of the puzzle back. Since then, the two have become fast friends, with Joey gaining ground as a duelist and as a person too.
On the flip side, Seto Kaiba. To summarize: Kaiba tries to kill Yugi and friends over a card game in the manga and serves as a villainous example of a deuteragonist. After losing to Yugi, Kaiba went on a journey of self-discovery which took up half the anime.
Yugi does develop as a duelist and a person, but more than half the anime is dedicated to his friends and Kaiba.
5) One Piece
One Piece is a swashbuckling story of pirates, adventure, and weird fruit that gives people superpowers. The Straw Hat crew are all deuteragonists to Monkey D. Luffy, as they all share an importance to the longrunning story. For the sake of simplicity, however, the only one we're focusing on is Roronoa Zoro.
Zoro is introduced as far back as One Piece's introductory arc, the Romance Dawn Arc. He's the first to join the crew, and the first to befriend Luffy. He made a promise to a friend named Kuina to become the world's greatest swordsman, and then became a bounty hunter in East Blue. He then arrived in Shells Town, wherein he was tied to a pole for killing a corrupt marine captain's son's pet wolf as it tried to kill a kid. Luffy helped him out of there, and the two defeated the corrupt marine captain and his son. The two then set off!
Throughout the series, Zoro throws off his lone wolf tendencies and becomes more of a team player. He gets downed by Mr. 1, a man made of steel in Alabasta and resolves to fight for the sake of others, especially after the Whiskey Peack arc, in which he fights off bounty hunters solo without alerting the crew.
Luffy himself has changed, growing slightly more serious as the series continues, but he's still a lovable oaf of a protagonist at the end of the day.
6) Fullmetal Alchemist
The adventure series Fullmetal Alchemist primarily chronicles the adventures of Edward and Alphonse Elric, two brothers who failed a human transmutation experiment to bring their mother back. They both lost something in the failed exchange: Ed lost his right arm and left leg; and Al his entire physical body, and was forced to exist as a soul tethered to a large steel armored suit.
The story may be about the two brothers, but the deuteragonist Alphonse gets a wealth of character development that Ed lacks. Al went from being a kid with no self reliance and a great deal of naivete to being fully self-reliant and sufficient under the training of Izumi Curtis. After losing his body and being bound to the armor, he just follows Ed around at first.
This changes when he starts getting his memory of the truth back, and Maes Hughes' death. Al repeatedly joins up with Mustang and helps him investigate Hughes' death due to feeling responsible. At first, Al firmly wants his human body back, then begins to think about staying in the armor, but ultimately decides that he cannot be lonely and disconnected from people any longer.
Al became his brother's pillar, so to speak. He transforms from a ghost trapped in a limbo state to a brave, smart, kind young man with his own goals in life.
In the Naruto series, the deuteragonist Sasuke Uchiha receives a substantial amount of character development over the main character Naruto. Sasuke goes from being the avenger of the Uchiha Clan, uncaring of his teammates or village, to actively wanting to kill them, to finally reconciling with them.
Sasuke's first goal was to kill his brother for the murder of their clan. After the Chunin Exams, he got manipulated by Orochimaru into betraying his village to accomplish this goal. He killed Orochimaru, Itachi and Danzo and was finally convinced to let go of his revenge after helping fight off Madara, Obito and seal away Kaguya. His and Naruto's final clash cemented his turn for the better.
Sasuke, as a deuteragonist, has since become a better man and father. He's more like Vegeta than anyone else, but he's let go of the rivalry. Whereas Naruto has excelled in power and gotten very serious — especially when he became Hokage — Naruto stopped developing after he managed to befriend Kurama.
8) Code Geass
The deuteragonist Suzaku Kururugi is technically an antagonist in Code Geass. What's interesting is how his development as a deuteragonist is parallel to protagonist Lelouch vi Britannia.
While Lelouch falls deeper into rebellion and lies with his Geass and the Black Knights, Suzaku gets duped into becoming The White Knight of Britannia. The system uses Suzaku and spits him out to the point where he is entirely disillusioned with it.
Suzaku goes from a well-meaning, if naive, kid wanting to help Japan live with Britannia to a traumatized, mentally unstable man who's had to shoulder the burden of Lelouch's plans.
9) Kill la Kill
The parallel story of Satsuki vs. Ryuko in Kill la Kill is a story of contrasts.
Deuteragonist Satsuki Kiriyuin begins Kill la Kill as the tyrannical overlord of Honno Town, speaking in Orwellian doublespeak ("Subjugation is Liberation" and "Fear is Freedom") and propping up a horrid class system where those who can fight, win, and lord it over others thrive.
Whereas main protagonist Ryuko Matoi lives in the slums of Honno Town with her adoptive family, the Mankanshokus, deuteragonist Satsuki is the epitome of the rich upper crust. Ryuko fights for the sake of her friends, and her own goal of finding out who killed her father and the mystery behind Senketsu. Satsuki seems to only fight to further the goals of the Kiriyuin conglomerate.
What's telling is the twist: Satsuki was working against her tyrannical mother Ragyo Kiriyuin the whole time. The only problem is that her cruel, manipulative tactics didn't work. Ragyo captured Satsuki and the Elite Four, Ryuko, and the anti-life fiber organization Nudist Beach rescued her. Satsuki ironically rescues Ryuko when she ends up brainwashed.
In the end, Ryuko and Satuski, the protagonist and deuteragonist, respectively, are revealed to be sisters. They both worked together after realizing how much alike they were, with Satsuki having her own "crazy band" to help her out in the form of her butler and the Elite Four.
In Bleach, everyone else gets character development instead of main protagonist Ichigo. Love interest Orihime has become a great fighter, not just a healer. Deuteragonist Rukia becomes more important as time goes on, even dropping the Ice Queen facade.
Rukia is interesting to talk about as a deuteragonist, because she starts as Ichigo's mentor and is responsible for giving him his powers. She was very serious at first and very cool to the point of coldness. She blamed herself for the hollowfication and death of Kaien Shiba, and masked everything she did under detatchment. She also seemed to just want to get rid of her life after that.
Ichigo helped her get past this. She is also excessively selfless to a fault. She spent so much time worrying about everyone else that she forgot about herself. After Ichigo rescued her from Soul Society, she got to care more about herself and likewise, help Ichigo.