Having been a veteran of numerous battlefields since the age of 9, Guts (Berserk) is a extremely formidable mercenary and powerful swordsman.
Tōshirō Hitsugaya (Bleach) was able to graduate from the Shinigami Academy in a single year with the highest written and performance scores in each of his classes and the youngest Soul Reaper to ever reach the rank of captain.
Ichigo Kurosaki (Bleach) became a Shingami at age 15, while still a teenager his astounding growth rate allows him to become one of the strongest Shinigami, surpassing even most Shinigami Captains.
Kenpachi Zaraki's (Bleach) potential as one of the strongest Shinigami was prominent in his boyhood, allowing him to kill hundreds of outlaws...
...and defeating captain Retsu Unohana, the supreme master swordswoman, who believed Kenpachi potential was stronger than herself.
Despite being a high-school student, Prince Akatsuki (Choujin Koukousei-tachi wa Isekai demo Yoyuu de Ikinuku you desu!) is the greatest magician in the world.
Despite being a high-school student, Ichijou Aoi (Choujin Koukousei-tachi wa Isekai demo Yoyuu de Ikinuku you desu!) is the strongest martial art master in the world.
While still a high-school student, Kanzaki Keine (Choujin Koukousei-tachi wa Isekai demo Yoyuu de Ikinuku you desu!) is the finest doctor in the world.
While still a high-school student, Sanada Masato (Choujin Koukousei-tachi wa Isekai demo Yoyuu de Ikinuku you desu!) is the most successful entrepreneur in the world.
While still a high-school student, Ooboshi Ringo (Choujin Koukousei-tachi wa Isekai demo Yoyuu de Ikinuku you desu!) is the most brilliant scientific genius the world has ever known.
Sarutobi Shinobu (Choujin Koukousei-tachi wa Isekai demo Yoyuu de Ikinuku you desu!) a highschool student who is also the world's best journalist.
While still a high-school student, Mikogami Tsukasa (Choujin Koukousei-tachi wa Isekai demo Yoyuu de Ikinuku you desu!) is a genius politician who served as the Prime Minister.
Layfon W. Alseif (Chrome Shelled Regios) is a natural-born prodigy among even the Twelve Heavens Blade, being capable of becoming one at the age of ten. It was stated by even his master Lintence that he could break-down and master Kei Techniques after just seeing them performed once.
Tokitou Muichirou (Demon Slayer: Kimetsu no Yaiba)
Vegeta (Dragon Ball series) showed tremendous power from a young age, even by the standards of First-Class warriors and the royal bloodline of the Saiyan race, breaking all previous records of Saiyan attributes.
Broly (Dragon Ball Super) was born with an unbelievable power level, even among Saiyans, which was just a prelude to his true potential
Frieza (Dragon Ball series) is a natural prodigy, having been born so powerful that he never had to train a day in his life...
...and when he did decide to train, he gained power comparable to gods within four months.
Trunks and Son Goten (Dragon Ball Z)
Rebecca (Dragonar Academy) is the second youngest Breeder to become a Dragonar.
Edward Elric (Fullmetal Alchemist), an alchemical prodigy, became a State Alchemist at age 12.
Mukuro, later Nobume Imai (Gintama) is a masterful assassin even as a child, her skills earned her the position as one of the Three Wings of Naraku, and often called the "Bastard Child of the Death God".
In addition to his magical aptitude, Negi Springfield's (Mahou Sensei Negima) intelligence is such that he became a homeroom teacher for high school girls at age 10.
Medaka Kurokami (Medaka Box) is a natural genius, progressing through infancy at an accelerated rate and able to surpass even adults in all fields before she was even two years old...
...and performing such feats as reading every single book in her parents' library in three months before she was even one.
Indra Ōtsutsuki (Naruto) was considered to be a prodigy, which led him to accomplish everything without the need for companions.
Sasori (Naruto) was considered as a child prodigy in the art of puppetry, mostly due to his loneliness in lack of parental love motivating his obsession in emotionless puppets.
As a young child who wasn't old enough to be a ninja yet, Zabuza Momochi (Naruto) effortlessly slaughtered over 100 Acemedy students without hesitation or pause earning the moniker of a Demon at a young age.
Itachi Uchiha (Naruto) has been heralded as a genius since childhood, as at age 13 he was selected to be a captain of ANBU Black Ops.
Reputed as the Second Coming of the Demon, Mangetsu Hōzuki (Naruto) was not only the youngest member of the previous generation of the Seven Ninja Swordsmen of the Mist but also mastered all of their individual swords.
Before leaving the Leaf Village, Sasuke Uchiha (Naruto) was hailed as a genius and was one of the most skilled fighters
of the village.
Boruto Uzamaki (Boruto: Naruto Next Generations) not only mastered three nature styles at the age of twelve but was also deemed as a chunin level ninja despite being a genin and well above his class by Kakashi Hatake himself.
Sarada Uchiha (Boruto: Naruto Next Generations) was able to master the Uchiha Fire Release at a very young age, inherited her mother intelligence and Chakra Enhanced Strength while also awakened her Sharingan at the age of 11 and inheriting her father's prodigious talent as an Uchiha.
Himawari Uzumaki (Boruto: Naruto Next Generations) not only awakened her Byakugan at a younger age then her mom and aunt, but also mastered use of the gentle fist on her very first try.
Tony Tony Chopper (One Piece) had become an outstanding doctor at the age of 15.
Even at the young age of 15, Kyros (One Piece) was already proficient in combat having fought an entire gang by himself and eventually becoming recognized as the strongest gladiator of Dressrossa colosseum at age 24.
Rob Lucci (One Piece) was a prodigy in the Rokushiki martial arts, he could slay 500 soldiers when he was only thirteen years old.
Monkey D. Luffy (One Piece) is the youngest of the Worst Generation, and one of the strongest pirates of all time. He became recognized as a Yonko at the age of 19.
Sabo (One Piece) is one of the most powerful fighters of the Revolutionary army and the youngest.
Minks (One Piece) are natural born warriors from birth.
Grount (One Piece) is prodigious marine soldier, his great fighting prowess allows him to become a Marine Captain at age 17.
Charlotte Linlin (One Piece) was born immensely powerful, able to overpower giants even at the age of 5.
Charlotte Katakuri (One Piece) is the second strongest member of the Big Mom Pirates, having never lost a single battle since the day he was born. Until he finally tasted defeat at the hands of Monkey D. Luffy.
Yukari Sendo (Rosario + Vampire) is smart enough to attend high school at age 11.
Erina Nakiri (Shokugeki No Soma) is a child prodigy able to speak at infant stage and gifted with unique ability called "Gods Tongue" making her genius in her academy.
Often described as a child of the war gods, Kyou (Kingdom) was a prodigy in both warfare and strategy from an early age and was considered the deadliest member of the Six Great Generals of Qin despite the being youngest. .
Due to him being sent to brutal battlefields from a very young age and mowing down countless masses of enemies, Earl Shi of the Wei Fire Dragons (Kingdom) at age 15 had already killed over 500 opponents.
Becaming the king of the Chouga tribe at a relatively young age, Yo Tan Wa (Kingdom) has done almost the impossible for somebody her age, having conquered over half the Mountain Tribes of Qin and earning the title of Da Shang Zhao.
Each of the Young Captains of the State of Qin (Kingdom) are considered "monsters" who posses astonishing talent in various fields of warfare such as tactical analysis, opportunity sense, skill adaptation and their respective fighting styles....
...Originally a servant and a slave, Shin of the Hi Shin Unit
trained himself in Swordsmanship
alongside his fellow servant Hyou and in the course of his life he has defeated far more experience opponents even before becoming a 100-man commander at the age of 14...
...Ou Hon, the extraordinarily adept leader of the Gyoku Hou Unit and powerful master in the art of Qiang (枪: Spear)...
...Mou Ten, leader of the Gaku Ka Unit, who is stated to be a prodigy even among his own famous Mou Family.
Noted by the elders of the Clan Shiyuu to be the most talented practitioner of the Priestess Dance
of her generation and a budding Tactical Genius
, Kyou Kai (Kingdom) is a dangerously fearsome master swordswoman and tactician at the age of 13.
Receiving special strategist recognition from the Chief of Military Arts at the age of 14, Ka Ryo Ten (Kingdom) is the skillful tactician and strategist of the Hi Shin Unit.
Kou Yoku of The Thunder (Kingdom)
Haku Rei of Chu (Kingdom) is the youngest member of the Ten Bows of China, extremely skilled archers throughout the 7 states of China, holding the spot of 3rd at the age of 18.
Kenshirō Kasumi (Fist of the Blue Sky) was already a full-fledged martial arts master by the age of 3 even before becoming the 62nd successor to the Hokuto Shin Ken.
his brother Raoh train daily, Toki (Fist of the North Star) demonstrated his own fighting ability by brutally beating a hunter who killed his pet dog and soon begin training in Hokuto Shin Ken/Big Dipper God Fist
and was considered by many to be the next successor due his elegent form in the martial art.
As a child, Kenshiro (Fist of the North Star) watched his adoptive brothers train in the art of Hokuto Shin Ken/Big Dipper God Fist and decided to join them in the fight to become the successor. Despite being younger and more naive than his older brothers, Kenshiro was a promising student who ultimately earned the title of successor.
Juza of the Clouds (Fist of the North Star) was considered the most gifted and powerful of the Nanto Goshasei at a early age.
Upon the birth of Sinbad (Magi: Adventure of Sinbad), Magi from all over the world sensed a great power had arrived in the world, referring to it as a "miracle child".
Sharrkan Amun Ra (Magi The Labyrinth of Magic) was prodigy in swordsmanship, able to defeat multiple strong adult robbers when he was nine years old.
Gin (Ginga: Nagareboshi Gin)
Christopher Thorndyke (Sonic X)
As a child, Stella Vermillion (Rakudai Kishi no Cavalry) was born with thirty times the amount of magic power as normal Blazers and has the potential to become one of the strongest.
Due to reincarnating and training since birth, Vandalieu (The Death Mage Who Doesn't Want a Fourth Time) became strong enough to kill Pure-breed vampires at age 8 and Evil Gods at age 9.
Since childhood, Suzaku Himejima (Highschool DxD) has outstanding talent in the spiritual arts of Shinto Mysticism, having been chosen to be the guardian of the Vermilion Bird at the age of 17.
DIO Brando (JoJo's Bizarre Adventure)
Being a natural born Ripple/Hamon user through his grandfather's bloodline, Caesar A. Zeppeli (JoJo's Bizarre Adventure Part II Battle Tendency) could unconsciously project its power from an early age.
During his childhood, Joseph Joestar (JoJo's Bizarre Adventure) developed and displayed his ability to use the Ripple/Hamon he inherited from his grandfather and mother.
An evil baby genius, Mannish Boy (JoJo's Bizarre Adventure Part III Stardust Crusaders) is a deadly Stand user of the nightmare wielding, Death 13.
Possessing one of the world's strongest Stand, Jotaro Kujo (JoJo's Bizarre Adventure Part III Stardust Crusaders) wields Star Platinum with the aptitude of a master at the young age of 17.