10 Strongest Anime Underdogs Who Became Overpowered by Pure Chance

There are plenty of stories in anime where the underdog completely defies expectations, despite starting their journey with little to no inherent strength or remarkable abilities. Whether it’s through a freak accident or unexpected encounters, these characters go on to find themselves in possession of some of the most powerful abilities in their respective universes.

While determination and perseverance play major roles in mastering these abilities, the circumstances behind their acquisition often happen by chance or simply being in the right place at the right time. Regardless of how their journeys unfold, each character proves that going from seemingly powerless to overwhelmingly strong can sometimes begin with one moment that happens to change everything.

Rudeus Greyrat

Before becoming one of the most powerful mages in Mushoku Tensei, Rudeus Greyrat lived his previous life as a deeply troubled, unemployed shut-in. Much of his original life was spent isolated, angry, and depressed, leading to a lifetime of regret and wasted potential. When he’s reincarnated into a new world as Rudeus, he’s given an unexpected second chance at life while retaining all his memories.

Rudeus is reborn with an extraordinary mana capacity that directly stems from a rare physiological advantage as he was born with the Laplace Factor. In this world, most infants with the Laplace Factor are stillborn, but because Rudeus still had all his memories when he was reincarnated, the body he now occupied survived. Paired with the fact that he was able to begin training early on in life, Rudeus had an unexpected and lucky head start.

Ichigo Kurosaki

Ichigo Kurosaki is the central hero of Bleach and one of the most powerful anime protagonists in shōnen. Although he could see ghosts since childhood, Ichigo initially lived as an ordinary high schooler until his life changed after an encounter with the Soul Reaper Rukia Kuchiki during a Hollow attack.

When things go badly wrong, Rukia has little choice but to transfer her power to him, allowing him to protect his family. What makes Ichigo even more remarkable is that his heritage encompasses several supernatural lineages, granting him a vast amount of spiritual power and abilities that other Soul Reapers don’t have. While later arcs of the story reveal that much of Ichigo’s life was constructed by Aizen, much of it was also a gamble that happened to pay off and play out exactly as Aizen wanted.

Akira Fudo

Devilman Crybaby centers on Akira Fudo, an initially ordinary and timid teenage boy. However, his life changes completely when his childhood friend, Ryo Asuka, brings him to an underground Sabbath party where he unexpectedly merges with the demon Amon, yet somehow retains control of his identity and consciousness rather than becoming a mindless host.

As a result, Akira gains the ability to transform into Devilman, granting him immense strength, speed, regeneration, and destructive power. While merging Akira with a demon was ultimately Ryo’s plan, he had no way of knowing which demon would possess him and likely did not expect Amon, one of the most powerful, to be the one to merge with Akira.

Yuji Itadori

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In Jujutsu Kaisen, before ever entering the world of jujutsu sorcery, Yuji Itadori was an ordinary high school student with above average physical strength and endurance. Despite having no formal experience with cursed energy, he finds himself at the center of jujutsu society after swallowing one of Ryomen Sukuna’s fingers to save his friends, turning himself into the vessel for the King of Curses.

Later arcs of Jujutsu Kaisen reveal that the circumstances leading up to Yuji’s birth was all constructed by Kenjaku to be the perfect vessel for Sukuna. That said, finding Sukuna’s finger, choosing to swallow it, being trained by the world’s most powerful sorcerer, effectively avoiding execution multiple times, and retaining Sukuna’s techniques were massive strokes of luck.

Hajime Nagumo

Hajime Nagumo was initially dismissed as the weakest member of his class in Arifureta. His Synergist ability offers little value in a world where combat strength determined everything and his situation turns desperate when he’s betrayed by a classmate during a dungeon expedition as he’s plunged down into the deadly pit of the Great Orcus Labyrinth where survival is seemingly impossible.

However, in order to survive, he consumes poisonous monster flesh and Ambrosia, a rare healing substance. The combination mutates his body, giving him monstrous traits and capabilities. He becomes physically stronger, but his mana capacity is also amplified, allowing him to become one of the most powerful figures in the world. However, had he fallen anywhere else, its likely he wouldn’t have survived.

Tetsuo Shima

Tetsuo Shima is the central antagonist of Akira, starting out as an insecure teenager who struggles to escape the shadow of his confident friend, Shotaro Kaneda. As a member of Neo-Tokyo’s Capsules biker gang, he deeply resents constantly needing protection and wishes that he could prove his own strength.

This chance comes unexpectedly after a motorcycle crash brings him into contact with Takashi, a young psychic being who is pursued by the military and soon finds that his latent potential has become unlocked. The accidental awakening goes on to become a catastrophic transformation, showing the darker side of what happens when immense power falls into the wrong hands.

Ken Kaneki

Tokyo Ghoul follows Ken Kaneki, a quiet college student whose life is upended following a near-fatal ghoul attack. Both he and the ghoul are severely injured and an emergency transplant gives Ken the ghoul’s organs, turning him into an artificial one-eyed ghoul who must eat human flesh to survive.

He also awakens with enhanced strength, rapid regeneration, and a powerful rinkaku kagune that he inherited from the ghoul who attacked him. However, this transformation was never part of some grand plan and Ken just so happened to be in the wrong place at the wrong time. Had he never met the ghoul, gone on the date, or arrived at the construction site, his life would look incredibly different.

Denji

Shueisha/Tatsuki Fujimoto

Raised in extreme poverty with a tremendous amount of debt, Chainsaw Man’s protagonist, Denji, spent his early years deeply burdened. His only real companion was his pet devil Pochita, but following a fatal encounter with the Zombie Devil, Pochita merges with Denji’s heart, transforming him into a human-devil hybrid known as Chainsaw Man.

When Denji first met Pochita, he had no idea that his pet devil was the Chainsaw Devil and had such immense abilities that other devils feared him. Due to the bond they shared, Pochita willingly chose to become Denji’s heart rather than acting due to an overarching plan or hidden agenda.

Kafka Hibino

For years, Kafka Hibino watches as his childhood dream slipped further out of reach as repeated failures kept him from joining the Defense Force in Kaiju No. 8. As his childhood friend, Mina Ashiro, rises through the ranks, Kafka works as part of a cleanup crew until a change to the recruitment age limit gives him one more chance to enlist.

The merge immediately grants Kafka such immense power that he goes from having no combat ability to becoming humanity’s last hope.

However, this second chance takes an unexpected turn when he’s suddenly fused with a creature that transforms Kafka into a kaiju himself, granting him immense strength, speed, durability, and regenerative abilities. The merge immediately grants Kafka such immense power that he goes from having no combat ability to becoming humanity’s last hope.

Sung Jinwoo

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At the start of Solo Leveling, Sung Jinwoo is known as the world’s weakest hunter, struggling to survive even the lowest-ranked dungeon raids. Then everything changes during the Double Dungeon Incident. On the brink of death, Jinwoo accepts a mysterious offer to become a Player at the last moment, gaining access to the System and its ability to let him level up through various quests and training.

While later developments reveal that this was part of a plan to find a suitable successor to the Shadow Monarch, the fact that it was Jinwoo who was chosen remains a remarkable stroke of luck. Not only are Double Dungeons exceedingly rare, but the fact that Jinwoo happened to meet certain requirements and accepted his role before his death were all a series of unlikely circumstances.