Several anime main characters' arcs have been astounding - their character sketches at the start and end of their storyline are often contrasting. These drastic changes revolve around their looks, ideals, or abilities. This is a testament to authors having no limit when it comes to experimentation within their manga/anime.
The characters in question could age and mature, have a change of heart, or develop a contrasting persona.
Anime main characters who were unrecognizable by the series' conclusion
1) Naruto Uzumaki (Naruto)
Naruto Uzumaki is one of the most popular anime main characters in the world. His journey began as a silly kid and ended as the most respectable Hokage. He started as a prankster, pining for attention and love.
However, through Naruto and then Naruto Shippuden, he showcases remarkable development in all aspects. Painful obstacles and near-death experiences did not deter him one bit. The result was his role as the 7th Hokage of the Hidden Leaf Village and possibly the strongest shinobi.
2) Asta (Black Clover)
Another well-known anime main character is Asta from Black Clover. In a world of Magic, he was born without any magical abilities. However, that turned out to be his power - he was a vessel who was capable of storing and utilizing the Anti-Magic bestowed upon him.
He continued to toil tirelessly with a single goal in mind: To become the Wizard King. Asta transitions from a common peasant to a hero who saves the Clover Kingdom multiple times.
3) Izuku Midoriya (My Hero Academia)
Izuku Midoriya is an anime main character who has skyrocketed in popularity and growth. The boy seen at the beginning of My Hero Academia and his current form are leagues apart.
Born Quirkless into a Quirk-run society, his fate changed when All Might chose him as the successor for One For All. Thus, he went from being a wimpy kid to an extremely powerful and serious contender for the title of #1 Hero. Inspired by All Might, his ideals remained somewhat unchanged but the events of the story strengthened him from within.
4) Gon Freecss(HunterxHunter)
Like typical Shonen anime main characters, Gon was an optimistic, adventure-loving, and extroverted young boy. His goals were to find his father, Ging, and explore mysterious lands as a Hunter. He was easygoing and likable, and quickly made friends wherever he went.
However, the world of HunterxHunter was a cruel place, and a young boy like Gon would soon find it too mentally and physically straining. Unlike Killua and Kurapika, Gon didn't receive any rigorous training from childhood. He became reckless, sometimes even ruthless, for the completion of his goals. During the Chimera Ants arc, he made a contract and gave up everything, including his Nen, in return for limitless power to kill Neferpitou and avenge his master, Kite.
After his rampage, he lost his ability to control Nen but his life was saved thanks to Alluka. Gon meets up with his father and moves back to his hometown. His change and subsequent fall into darkness was the result of his youthful inexperience. In the list of popular anime main characters, he would be more of an anti-hero.
5) Eren Yaeger (Attack on Titan)
As is the case of many anime main characters, their character development is usually geared towards a transition for the better. However, it was not as simple when it came to Attack on Titan's Eren Yeager.
His surroundings played a major role in his twisted behavior and ideals. However, nobody expected him to turn into a maniac who viewed genocide as a viable solution. He wanted peace for Paradis but was not open to any other method of ensuring it. His drastic change will forever be a controversial topic among anime/manga fans.
6) Kaneki Ken (Tokyo Ghoul)
Kaneki Ken is possibly the most intriguing character on this list of anime main characters. With each of the seasons, a different version of the protagonist is seen. He underwent some serious changes and eventually stands as one of the most tragic anime storylines.
Rize Kamishiro transitioned into one of the most powerful and feared Ghouls ever. His growth was reflected each time in his appearance and hair color - white meaning Ghoulhood and black implying humanity.
7) Hinata Shoyo (Haikyuu!!)
Hinata Shoyo from Haikyuu!! is a must on this list of anime main characters. The series showcased his growth brilliantly. He didn't start as a great player, but he seemed to be hiding immense potential.
Facing better plays, he was exposed to the gap in skill between them and him. Thus, through intense training and numerous matches, he gradually gained experience and transformed into one of his team's key players.
8) Thorfinn (Vinland Saga)
Another popular name when it comes to anime main characters is Vinland Saga's Thorfinn. His story, although packed with action, was gut-wrenching. While seeking revenge on Askellad for murdering his father, he practically grew up on the battlefield.
He took numerous lives and caused destruction where he went. All this caught up to him and he was eventually captured and enslaved. However, an encounter with Einar changed his perspective entirely and thus began his redemption arc.
9) Shoya Ishida (A Silent Voice)
One of the most well-known anime main characters, Shoya Ishida went from bullying to wanting to repent for his sins. Although a young boy, he behaved terribly towards a deaf transfer student, Shoko Nishimiya, who in turn, behaved extremely sweetly with him. Later, he realized the extent of his misbehavior and felt an immense guilt within.
Thus, he sought redemption - however, it did take quite a bit to earn her trust and more importantly, find peace within himself. Nonetheless, he succeeded in doing so and even saved Shoko from taking her own life.
With a simple story on the surface, he is one of those anime main characters whose development is quite heart-touching.
10) Shigeo Kageyama (Mob Psycho)
When it comes to well-developed anime main characters, it is impossible to miss Shigeo Kageyama. The story follows his journey of balancing his academic student life and his extraordinary esper abilities. It is considered one of the most well-written stories in anime/manga.
He starts the series as an introvert who keeps to himself, speaks less of his emotions, and has issues socializing. However, his journey is a metaphorical depiction of a kid growing into an adult who learns to deal with the complexities of life.