Every great anime needs a strong main character, but the protagonist isn’t always the reason fans fall in love with a series. In many cases, it’s the rival, mentor, best friend, or even the villain who steals every scene they appear in. These supporting characters often have unique personalities, emotional backstories, or unforgettable moments that leave a bigger impression than the hero. Years after an anime ends, fans are still talking about these characters, creating fan art, sharing clips, and debating why they deserved even more screen time.
This list highlights 14 anime side characters who outshone their own protagonists and became fan favorites. From brilliant rivals to unforgettable mentors and breakout supporting characters, each entry earned its popularity through memorable writing and standout performances.
1. Killua Zoldyck
While Gon Freecss is the main protagonist of Hunter × Hunter, many fans believe Killua Zoldyck is the character who truly steals the spotlight. From his very first appearance, Killua stands out with his sharp intelligence, sarcastic humor, and calm personality. Unlike Gon, who dreams of finding his father and exploring the world, Killua carries the weight of a painful childhood that shapes every decision he makes.
Born into the infamous Zoldyck family, Killua was trained from a young age to become a professional assassin. He learned how to fight, torture, and kill long before he experienced a normal childhood. Despite his incredible skills, Killua never wanted the life his family chose for him. Instead, he longs for freedom and the chance to make his own decisions. This inner conflict makes his journey one of the most emotional stories in the series.
One of the biggest reasons fans connect with Killua is his friendship with Gon. Although he is stronger and more experienced, Killua is always willing to protect his best friend. Their bond becomes the heart of Hunter × Hunter, showing how trust and friendship can help someone overcome years of fear and emotional pain.
Killua’s relationship with his younger sister, Alluka, adds even more depth to his character. His determination to protect her, despite the danger surrounding her unique abilities, shows his caring side and highlights how much he has grown since leaving his family behind.
Over the years, Killua has consistently ranked among the most popular Hunter × Hunter characters in fan polls around the world.
2. Levi Ackerman
Attack on Titan is filled with unforgettable characters, but few have earned as much love from fans as Levi Ackerman. Although Eren Yeager is the main protagonist, Levi often steals the spotlight whenever he appears. Known as humanity’s strongest soldier, he quickly became one of the most popular characters in the series thanks to his incredible fighting skills, calm personality, and unforgettable leadership.
Levi is famous for his unmatched abilities on the battlefield. Whether he’s facing Titans or powerful human enemies, he remains calm under pressure and always puts the mission first. His fast-paced action scenes are among the best in Attack on Titan and have become some of the most-watched and shared moments in anime.
However, Levi’s popularity goes far beyond his strength. What truly makes him special is the emotional depth hidden beneath his quiet personality. Throughout the story, he loses many friends and teammates, yet he rarely speaks openly about his pain. Instead, the series shows his grief through small actions, silent moments, and the determination to keep moving forward. This subtle storytelling makes his character feel realistic and relatable.
Levi’s relationship with Commander Erwin Smith is another reason fans admire him. The trust and respect they share lead to some of the anime’s most emotional moments. His loyalty to his comrades and his willingness to carry the burden of difficult decisions show that true strength is about more than winning battles.
Years after Attack on Titan ended, Levi continues to rank among the most popular anime characters worldwide. His unforgettable action scenes, emotional character development, and quiet resilience have made him much more than a supporting character.
3. Kakashi Hatake
Naruto Uzumaki is the heart of Naruto, but many fans believe Kakashi Hatake is the character who leaves the biggest impression. As the leader of Team 7, Kakashi quickly became a fan favorite with his calm personality, mysterious past, and incredible ninja skills. His relaxed attitude, habit of arriving late, and love for reading novels make him entertaining, but there’s much more to his character than first meets the eye.
Behind Kakashi’s calm smile is a life filled with loss and regret. He experienced tragedy at a young age, losing people who were closest to him and carrying the guilt of those events for years. Instead of letting his past define him, Kakashi uses those painful experiences to become a better teacher. He wants Naruto, Sasuke, and Sakura to avoid the mistakes that haunted his own generation, making him one of the series’ most caring mentors.
Kakashi’s growth throughout the story is one of the strongest character arcs in the franchise. He begins as a quiet shinobi who keeps his emotions hidden but slowly learns to trust others and accept the responsibilities of leadership. Over time, he becomes one of the Hidden Leaf Village’s greatest protectors and eventually serves as the Sixth Hokage, earning the respect of both his friends and former enemies.
Even years after Naruto ended, Kakashi remains one of the franchise’s most beloved characters. His emotional journey, unforgettable battles, and inspiring leadership have made him much more than a supporting character. For many fans, Kakashi Hatake is one of the greatest mentors and side characters in anime history.
4. Sebastian Michaelis
Although Black Butler follows the story of Ciel Phantomhive, it’s Sebastian Michaelis who often steals the spotlight. From the moment he appears, Sebastian leaves a lasting impression with his calm confidence, perfect manners, and incredible abilities. As Ciel’s loyal butler, he handles every task flawlessly, whether it’s preparing tea, protecting the mansion, or defeating dangerous enemies.
What makes Sebastian such a fascinating character is the mystery surrounding him. While he appears to be the perfect servant, he is actually a powerful demon bound by a contract with Ciel. Behind his polite smile and elegant appearance lies a dangerous being who is always waiting for the day he can claim Ciel’s soul. This constant contrast between his refined behavior and his true nature keeps viewers curious throughout the series.
Sebastian is also one of the strongest characters in Black Butler. His supernatural speed, strength, and intelligence allow him to overcome almost any challenge with ease. Yet he rarely loses his composure, making every fight look effortless. His calm attitude and sharp sense of humor add charm to the series, balancing its darker moments with memorable interactions.
Beyond his impressive abilities, Sebastian’s unique design has made him one of anime’s most recognizable characters. His black suit, white gloves, and red eyes have inspired countless cosplay performances, fan art, and merchandise around the world. Even people who haven’t watched Black Butler often recognize Sebastian by appearance alone.
5. L Lawliet
Fans believe L is the true star of the series. From his first appearance, L stands out with his unusual personality, brilliant mind, and mysterious presence. He sits in strange positions, loves eating sweets, and rarely behaves like a typical detective, yet he quickly proves why he is considered the world’s greatest investigator.
Unlike most anime characters, L doesn’t rely on supernatural powers or physical strength. His greatest weapon is his intelligence. As mysterious deaths begin happening around the world, L is the first person capable of challenging Kira. Using careful observation, logical thinking, and clever planning, he slowly uncovers clues that bring him closer to the truth. Every move he makes forces Light to think several steps ahead, creating one of the most exciting mind games in anime history.
One of the reasons fans love L is his unique relationship with Light. Even though he strongly suspects Light is Kira, he chooses to work alongside him to gather more evidence. Their conversations are filled with hidden meanings, making every episode feel like a psychological battle instead of a simple detective story. This rivalry is widely regarded as one of the greatest hero-versus-rival matchups in anime.
L’s quirky habits also make him unforgettable. His unusual sitting posture, calm expression, and love of desserts add humor to an otherwise dark and serious story. These small details make him feel different from almost every other detective in anime.
6. Escanor
Meliodas may be the main hero of The Seven Deadly Sins, but for many fans, Escanor is the character who steals every scene he appears in. As the Lion’s Sin of Pride, Escanor quickly became one of the series’ biggest fan favorites thanks to his incredible power, unforgettable confidence, and emotional character arc. Every time he enters a battle, viewers know they’re about to witness one of the anime’s most exciting moments.
What makes Escanor unique is his extraordinary ability. During the night, he is quiet, gentle, and lacks confidence. However, as the sun begins to rise, his strength grows with every passing minute. At noon, he reaches his strongest form, becoming one of the most powerful characters in the entire series. His famous battles showcase overwhelming strength and some of the most memorable action scenes in The Seven Deadly Sins.
Despite his incredible power, Escanor is much more than an unstoppable fighter. His story also explores the burden of carrying strength that few people can understand. While he proudly accepts his role as the Lion’s Sin of Pride, he also faces loneliness and the emotional cost of possessing such extraordinary abilities. These quieter moments reveal a kind and humble side that makes him even more likable.
Escanor’s confidence has also produced some of the most iconic quotes in the series. His fearless attitude, combined with his respect for worthy opponents, has made him one of the most memorable personalities in modern shonen anime.
7. Todoroki Shoto
From the moment Todoroki Shoto appears, he stands out with his unique half-fire, half-ice Quirk and his quiet personality. However, what truly makes him memorable isn’t his incredible power. It’s the emotional story behind it.
Todoroki grew up in one of the most troubled families in the series. His father, Endeavor, pushed him from a young age to become the perfect hero, believing Shoto was the key to surpassing All Might. That constant pressure and emotional abuse left deep scars, causing Todoroki to reject the fire side of his Quirk because it reminded him of his father. Instead of focusing on flashy battles, the series spends time exploring his pain, anger, and struggle to decide who he wants to become.
One of the most emotional moments in My Hero Academia comes during the U.A. Sports Festival, when Midoriya encourages Todoroki to stop running from his past and use his full power. That fight marks the beginning of Todoroki’s journey toward accepting himself rather than letting his family history define him.
As the story continues, Todoroki slowly rebuilds his relationship with his mother and faces difficult questions about forgiving his father. Those personal conflicts make him feel more realistic than many typical anime rivals. His growth happens little by little, making every step feel earned.
It’s no surprise that Todoroki regularly ranks near the top of official popularity polls and remains one of the franchise’s most loved characters. While Midoriya carries the story as its main protagonist, many viewers connect more deeply with Todoroki’s emotional journey, making him one of the best-written side characters in modern shonen anime.
8. Kamina
Many anime fans remember Tengen Toppa Gurren Lagann because of Simon’s journey, but it’s Kamina who gives the series its heart and unforgettable energy. Even though he isn’t the main protagonist, Kamina’s confidence, passion, and fearless attitude make him one of the most iconic side characters in anime.
Kamina dreams bigger than anyone else around him. He refuses to accept limits, no matter how impossible the situation looks. Whether he’s facing powerful enemies or encouraging his friends, he always believes that determination is stronger than fear. His famous speeches about believing in yourself have become some of the most quoted lines in anime history, inspiring fans long after the series first aired.
What makes Kamina so memorable is that he changes everyone around him. Simon starts the story as a shy and insecure boy who doubts his own abilities. Kamina is the first person to truly believe in him and constantly pushes him to become stronger. Instead of solving every problem himself, Kamina inspires others to discover their own strength. That influence continues throughout the entire series, even after his own role in the story changes.
Kamina’s larger-than-life personality also brings a perfect balance of humor, excitement, and emotion. One moment he is making bold promises that seem impossible, and the next he is risking everything to protect his friends. Those moments helped turn him into one of anime’s most beloved mentor figures.
More than a decade after Gurren Lagann aired, Kamina remains a fan favorite. His speeches are still widely shared on YouTube, social media, and anime forums whenever fans talk about motivation and never giving up. While Simon is the hero who completes the journey, many viewers believe Kamina is the character who defines the spirit of the entire series.
9. Reigen Arataka
When people first meet Reigen Arataka in Mob Psycho 100, he seems like nothing more than a smooth-talking fake psychic who makes a living by convincing people he can solve supernatural problems. The funny part is that Reigen doesn’t have any psychic powers at all. Instead, he depends on confidence, clever thinking, and his ability to talk his way through almost any situation. That makes him one of the funniest characters in the series, but there’s much more to him than comedy.
As the story moves forward, Reigen proves that he is far more important than fans first expect. While Mob has incredible psychic abilities, he struggles with emotions, friendships, and self-confidence. Reigen becomes the person who teaches him that his powers don’t define who he is. He encourages Mob to become a better person instead of simply becoming a stronger psychic, giving the series some of its most meaningful life lessons.
One of Reigen’s biggest strengths is that he feels like a real person. He makes mistakes, hides his insecurities, and sometimes takes advantage of situations to keep his business running. At the same time, he always steps up when Mob truly needs him. His flaws make him believable, while his kindness makes him easy to respect.
Many fans consider Reigen the emotional heart of Mob Psycho 100. His relationship with Mob grows from a funny mentor-student partnership into one of the best friendships in modern anime. Even without supernatural powers, he often becomes the bravest person in the room because he chooses to protect others despite knowing the risks.
10. Roronoa Zoro
In a series filled with unforgettable characters, Roronoa Zoro has become one of the biggest reasons fans keep coming back to One Piece. While Monkey D. Luffy leads the Straw Hat Pirates as the future Pirate King, many viewers consider Zoro the crew’s backbone. His calm personality, unwavering loyalty, and incredible swordsmanship have made him one of the most popular side characters in anime.
Zoro joins Luffy at the very beginning of the adventure, and from that moment, he proves he is much more than just the captain’s strongest fighter. He has a dream of his own to become the world’s greatest swordsman by honoring a promise he made to his childhood friend, Kuina. That personal goal gives his journey real emotional weight and makes every battle feel meaningful.
One of Zoro’s greatest strengths is his loyalty. No matter how dangerous the situation becomes, he never hesitates to stand beside his captain and protect his crew. Some of the most unforgettable moments in One Piece come from Zoro putting himself in harm’s way for his friends, showing why he has earned so much respect from both the characters in the story and the fans watching.
At the same time, Zoro isn’t serious all the time. His constant arguments with Sanji create some of the funniest moments in the series, while his terrible sense of direction has become a running joke that fans still love years later. That balance of humor and intensity makes him one of the most entertaining characters in the Straw Hat crew.
It’s no surprise that Zoro regularly ranks near the top of official popularity polls and remains one of the best-selling characters in One Piece merchandise. Although Luffy is the hero of the story, Zoro’s determination, memorable fights, and unforgettable personality have helped him build a fan following that is every bit as passionate. For many fans, he is just as iconic as the captain himself.
11. Nagi Seishiro
Blue Lock introduces plenty of talented strikers, but few have captured fans’ attention as quickly as Seishiro Nagi. Although Yoichi Isagi is the main character leading the story, Nagi has become one of the franchise’s biggest fan favorites thanks to his incredible talent, unique personality, and steady character growth.
When Nagi first appears, he doesn’t seem interested in soccer at all. He only started playing because his friend Reo Mikage encouraged him, and he often acts like everything is too much effort. Despite that attitude, his natural ability is unbelievable. His first touch, ball control, and creativity on the field immediately set him apart from the other players competing in Blue Lock.
However, what makes Nagi such a compelling character isn’t just his skill. As the competition becomes more intense, he realizes that raw talent alone isn’t enough. For the first time in his life, he experiences failure, frustration, and the desire to improve. Watching Nagi slowly develop a competitive mindset is one of the most satisfying parts of the series. Instead of relying only on his natural gifts, he begins working harder and discovering what it truly means to chase a dream.
His relationships with Reo and Isagi also add depth to his story. Their friendships, rivalries, and changing goals push Nagi to grow both as a player and as a person. These interactions give him emotional development that goes far beyond exciting soccer matches.
Today, Nagi is one of the most popular characters in Blue Lock. His incredible goals and highlight plays are regularly shared across YouTube, Instagram, and other anime communities, often attracting more attention than scenes focused on the main protagonist. While Isagi drives the story forward, many fans believe Nagi’s journey from an unmotivated genius to a determined competitor is even more rewarding to watch, making him one of the standout side characters in modern sports anime.
12. Yoruichi Shihouin
Bleach is filled with memorable characters, but Yoruichi Shihouin is one of the few who manages to steal the spotlight almost every time she appears. While Ichigo Kurosaki is the hero who drives the story forward, many fans remember Yoruichi for her confidence, incredible strength, and fun personality. She isn’t on screen as often as some of the main cast, but every appearance leaves a lasting impression.
When Yoruichi is first introduced, she keeps her true identity hidden, making her one of the series’ biggest early surprises. As the story unfolds, viewers learn that she is the former head of the powerful Shihouin Clan and a former captain-level Soul Reaper. That reveal completely changes how fans see her. She isn’t just a helpful ally; she is one of the strongest and most skilled fighters in the Soul Society.
Yoruichi also plays an important role in Ichigo’s growth. During one of the series’ most important training arcs, she teaches him new techniques and helps prepare him for the dangerous battles ahead. Instead of acting like a strict mentor, she mixes her lessons with humor and confidence, making their interactions both entertaining and meaningful. Even in the middle of life-or-death situations, she stays calm and rarely loses her sense of humor.
Another reason fans love Yoruichi is her unique fighting style. Rather than relying only on a sword, she combines incredible speed, hand-to-hand combat, and powerful techniques that make every fight exciting to watch. Her battles remain some of the most memorable moments in Bleach.
13. Vegeta
When people think of Dragon Ball, Goku is usually the first character that comes to mind. However, for many longtime fans, Vegeta is the character with the most rewarding journey in the entire franchise. His transformation over the years is one of the biggest reasons he continues to be one of anime’s most popular side characters.
Vegeta doesn’t begin as a hero. He arrives on Earth as a ruthless Saiyan prince who believes strength is everything. Proud of his royal bloodline, he looks down on almost everyone around him and sees Goku as nothing more than a low-class warrior. His goal is simple: become the strongest and defeat anyone who stands in his way. That arrogance makes him one of the series’ most memorable early villains.
What makes Vegeta’s story so compelling is that he doesn’t suddenly become a good person overnight. His growth happens slowly across multiple story arcs. As he fights alongside the Z Fighters, builds a family with Bulma, and becomes a father to Trunks, he begins to change without losing the personality that made fans love him in the first place. He remains proud, stubborn, and fiercely competitive, especially when it comes to Goku. Instead of abandoning those traits, the series shows how he learns to use them for the people he cares about.
Some of Vegeta’s most emotional moments come when he chooses to protect his family rather than chase his own pride. Those scenes carry real impact because viewers have seen how far he has come since his first appearance. His development feels natural and earned, making him one of the best examples of long-term character growth in shonen anime.
Even after decades, Vegeta continues to rank near the top of Dragon Ball popularity polls and remains a fan favorite across anime communities. His unforgettable battles, personal growth, and never-give-up attitude have helped him build a loyal fanbase that, in many cases, is just as passionate as Goku’s. For countless viewers, Vegeta is the character who truly steals the spotlight.
14. Kenpachi Zaraki
Among the many powerful Soul Reapers in Bleach, Kenpachi Zaraki is the one who always stands out. While other captains rely on strategy, discipline, or special techniques, Kenpachi lives for one thing: fighting strong opponents. Every battle is an opportunity for him to test his limits, and that fearless attitude has made him one of the most popular characters in the series.
From his very first appearance, Kenpachi leaves a lasting impression. His scar-covered face, wild hairstyle, and intimidating spiritual pressure make it clear that he is unlike any other captain in the Soul Society. He doesn’t care about status or recognition. Instead, he searches for opponents who can give him the challenge he has been waiting for. That simple goal makes his fights exciting because fans know he never holds back when facing a worthy enemy.
Despite his tough personality, Kenpachi isn’t just a fearless warrior. His relationship with his lieutenant, Yachiru Kusajishi, reveals a softer and more caring side that many viewers don’t expect. The way the two trust and support each other adds warmth to his character and shows that there is more to him than endless battles.
Another reason fans love Kenpachi is his unique fighting style. He doesn’t rely on complicated plans or flashy techniques. Instead, he charges straight into battle with overwhelming strength and confidence. As the story progresses, the series slowly reveals just how much power he has been holding back, making every new fight even more exciting than the last.
