In the world of anime, there are hundreds of characters who get stronger over the course of a storyline, such as by training hard to learn a new technique or acquiring a new spell or weapon to enhance their combat abilities. Shonen and seinen anime series are especially known for this.
Anime heroes and villains alike can get stronger over the course of a story, not to mention some antiheroes, and some characters power up just once, while others steadily get stronger and stronger. In fact, it seems like these characters gain new powers or abilities every time they appear. Who are these anime characters, and what can they do?
10 Lucy Heartfilia Keeps Getting New Keys (Fairy Tail)
Lucy Heartfilia is one of the newest wizards in the Fairy Tail guild, and she is also a Celestial wizard, a summoner who can call upon spirits to aid them in battle. At first, Lucy had only a few gold and silver keys in her inventory, but that soon changed.
During the many episodes of Fairy Tail, Lucy acquired several more gold keys to expand her arsenal, and that's a quick way for her to power up. She also started using Star Dresses, or combat outfits that matched her astrological spirits. She even used Fairy Sphere later on, and could perform Unison Raids after a point.
9 Sasuke Uchiha Will Take Any Power He Can Get (Naruto)
It's not just anime heroes who slowly and surely build up their physical or magical abilities. Some anime villains have to take time to build up all their powers, and that includes the rogue Sasuke Uchiha, who was a villain for much of Naruto: Shippuden.
Sasuke was born with the Sharingan, but he wasn't quite as talented as his brother, Itachi. He got stronger when Orochimaru gave him a curse mark, and then he learned how to perform the Chidori as well. Sasuke later acquired the Mangekyo Sharingan, the Rinnegan eyes, curse mark state 2, and more.
8 Ichigo Kurosaki Has Trained Many Times (Bleach)
Ichigo Kurosaki was born with some spiritual gifts, but he had to train long and hard to become a powerful fighter, and it all started when Rukia Kuchiki lent him her Soul Reaper powers in Season 1. Ichigo used a generic and nameless zanpakuto at the time, until he soon acquired Zangetsu, his real zanpakuto.
Ichigo trained with Kisuke Urahara, then again with Yoruichi Shihoin the rogue to obtain his bankai, Tensa Zangetsu. After that, Ichigo learned to control his Hollow mask to become even stronger, and then he learned the final Getsuga Tensho from his father. He gets stronger in every fight, it seems.
7 Ken Kaneki Evolved As A Ghoul (Tokyo Ghoul)
Ken Kaneki is a dark antihero, and at first, he never meant to be a fighter at all. But when Rize Kamishiro's organs were transplanted into him, he became a half-ghoul, boosting his physical endurance and strength. He got stronger when he started training with Touka Kirishima, his friend, and other mentors.
Ken got even stronger when he cannibalized Yamori's body and obtained a centipede-like kakuja, which impressed and frightened his enemies and allies alike. He now has the strength and resolve of a true ghoul warrior, but he was still no match for the talented Kisho Arima.
6 Eren Yeager Obtained Three Titan Shifter Powers (Attack On Titan)
Eren Yeager was once an ordinary boy, but everything changed when the Colossal Titan and the Armored Titan stormed the walls and brought war to Paradis Island. Eren trained as a soldier and thus became stronger, but he wouldn't truly dominate the battlefield until his Attack Titan form entered the picture.
Eren got a massive boost when he started using his Attack Titan form at will, and he still wasn't done powering up. He later fought and consumed Lara Tybur, thus acquiring her War Hammer Titan form. And when Eren got his hands on the Founding Titan as well, he was strong enough to defy all his enemies and launch the Rumbling.
5 Avatar Aang Learned All The Elements (Avatar: The Last Airbender)
Avatar Aang was born with the potential to bend all four elements, but in his own era, he only trained in the ways of airbending before he ran off alone and ended up frozen in that iceberg for a full century. He awoke in a new era, and he needed to catch up and end the Hundred-Year War somehow.
Aang grew stronger when he learned waterbending from Katara and master Pakku, and then he learned how to bend earth from Toph Beifong. After that, he learned firebending from Zuko and the two last dragons, Ran and Shaw, and he even learned "energybending" from a lion-turtle. He is now a true master bender.
4 Izuku Midoriya Won't Stop Training (My Hero Academia)
Izuku Midoriya is the shonen protagonist of My Hero Academia, and that, combined with his excellent work ethic, means he was bound to get stronger and stronger over time. Students like Fumikage Tokoyami and Shoto Todoroki are born powerful, but Izuku had to work at it.
Early on, Izuku trained for an entire year just to obtain One For All, let alone use it. Izuku became even stronger when he figured out Shoot Style and Full Cowling, and he upgraded his hero costume to match. More recently, he unlocked the power of Blackwhip as well, and he will manifest even more imprinted Quirks in One For All before long.
3 Rimuru Tempest Gains Lots Of Skills & Attributes (That Time I Got Reincarnated As A Slime)
A Japanese salaryman got stabbed to death, then was reborn in a fantasy realm as a humble blue slime with a few attributes, including basic telepathy and the Predator skill. Now known as Rimuru Tempest, this isekai hero quickly became a true fantasy powerhouse, mainly by consuming other people or monsters with Predator.
Rimuru gained dozens of new powers, from steely spider threads to black fire and rapid regeneration, and he later became a True Demon Lord to boost his powers even further. When he did that, he captured lost souls and actually revived the dead.
2 Naofumi Iwatani Steadily Leveled Up (The Rising Of The Shield Hero)
Naofumi Iwatani is also an isekai hero, but instead of the Predator skill and a slime body, he has access to shields, and no other equipment type. Naofumi's new life was like a video game, including experience points and an RPG-style HUD, and he patiently leveled up in order to deal with the deadly Waves.
Naofumi's stats kept going up and up, and he assembled an impressive collection of diverse shields to handle any type of enemy. He even gained some shields with limited offensive capabilities, and he could also use a dark berserker-type shield power in emergencies. He's come a long way.
1 Luffy Has Become Incredibly Powerful Over Time (One Piece)
As a true shonen protagonist, Monkey D. Luffy has a dream -- to become pirate king -- and the patience to slowly and surely enhance his fighting style over time. The One Piece series has an exciting combat system and fairly smooth power creep, so fans can watch as Luffy steadily gets stronger.
Luffy has learned all kinds of techniques with the Gum-Gum Fruit, and he has learned to use the Gears to get bursts of strength, all the way up to Gear Four, which is impressive. He later learned to use Haki as well, which helped push him to the next level.