@KairiJun:

Good choice, though the story does begin after he leaves Chronos.

@NagisaNeko3:

Nope. Not at all.

I found a good anime one.

<----- Rintaro Okabe from Steins;Gate

Okabe starts as this cocky madman who wants nothing but the chaotic control of science. He's rather a moron at first, chasing pipe dreams and believing in secret organizations that wish to ruin him. With the hopeless lab assistants Shiina Mayuri and Hashida Daru in tie, he hasn't a prayer. That is, until he meets Makise Kurisu, a genius of psychology and mental distortion. Together they pioneer the science of time-travel, and all seems okay.

Things go downhill fast in Episode 10, when history begins to be re-written so much that entire portions of Japan are shaped to fit the new reality. Mega organization SERN, real-life creators of the Large Hadron Collider, catch on and begin to sniff around. As the lab adds more members, Okabe becomes overly protective to a point of self-sacrifice, betraying his code of the mad scientist. It isn't until Episode 12 that his character development reaches critical mass.

On celebrating the success of the continued upgrading of the time machine, the lab is betrayed by lab member Moeke Kiryu, a special operative of SERN. She takes Okabe, Daru, and Kurisu into questioning and, having no need for her, shoots Mayuri point blank. Okabe makes a last ditch effort to rewrite the past, sending information back regarding the shooting. No matter what he does, no matter what he tries, the universe has sentenced Mayrui to death. It's in these episodes Okabe becomes a tragic character, no longer hellbent on destroying, now only wishing to save the one thing he loves the most without letting anyone help him.

The mental anguish begins to get the best of him, realizing its all his fault. Every event that destroys his sanity is his fault and there's nothing he can do. It's only when Kurisu begins to aid him that his intuitiveness returns. A mad scientist not from start to finish, and he's all the greater for it.

@Hisaishi:

So true!

I won't say how they changed so I'll just say their names ^^;

Griffith from Berserk
Tsuna from KHR!
Kyoko from Skip Beat!

The most dramatic character change I witnessed is that of Judai Yuki in Yu-Gi-Oh Duel Monsters GX. In the first 3 seasons,Judai is a happy go lucky boy with an innocent and naive personality. He easily smiles and is friends with everyone. Everybody wants to be his friend. But toward the end of season 3 he changed due to circumstances. Judai duels Yubel and has to fuse his soul with hers,Fights a Yubel possessed Johan,and stays in the dimension and appears at the end of season 3/beginning of season 4. By season 4 we see a completely different Judai. He doesn't know if anyone will accept him with Yubel fused in his soul.Judai is completely different in season 4. He's more of a loner,he avoids his friends,and he's a lot more serious. His hair is longer and his eyes are narrowed to show this dramatic change.But he learns that his friends will always be there for him no matter what. By the end of the season, he's a completely new Judai.

Hmm, I couldn't really think of anything good, but I'd say Saya from Blood+, and Yukiteru from Future Diary/Mirai Nikki.

Saya goes from being a bubble-headed (yes) high schooler to a chiropteran killing machine over the course of one night. She started as a fairly cheerful character, and turned into a kind of...pessimist.

Yukiteru...he's a spineless coward, to say the least (Future Diary is a good series, though). Yet...as naive as he can be, later in the series, he's wielding a machine gun and threatening the mayor of his city! Nevertheless...he goes back to being his "normal self" afterwards.

Now that I think about it...I also want to point out Azusa from Gakuen Prince (a hilarious and ridiculous series - not for the faint of heart). One minute, he's aggressive and about to get in a fight, the next, he's whining and hiding behind his half?girlfriend!

My brother did point out before that Ryuji, the main male character of Toradora, had a major character change. Initially, students and teachers feared him because of his eyes (which I think is pretty stupid). But as the series progressed, we now see people not being afraid of him anymore for some reason.

Granted, I only watched a few episodes of the show. But that character change did look quite dramatic.

Main cast of Shugo Chara and Zombie-Loan.

Mima Kirigoe from Perfect Blue. Can you say "near-fatal downward spiral", kids?

@thelostsindar:

I second Yoko! In the first book especially, where her character changes most dramatically.

I would say Train from Black Cat, I'm not sure if he can be counted though.

@:

I'd actually say every girl (except for Mami, for good reasons) all had really dramatic turns. Madoka became self-confident, Sayaka became recklessly vicious, and Kyoko learned to open up. By the end, each had just about flipped a fragment of their personality.

Well Adam, if you can use the Tomb Raider game, I can name a video game as well.

Metal Gear Rising; Revengeance has long time Metal Gear character Raiden as the main star. He's now a cyborg/assassin/samurai/Jesus whose work with Maverick Securities has turned to taking down Desperado Enterprises, merchants of death who develop technology made solely to destabilize peaceful nations.

In one fight, Raiden must kill police officers who were assigned to guard the World Marshal Tower, part of Desperado's property acquisitions. He becomes conflicted throughout his fights as he realizes these men weren't guilty of any crime but following orders. He begins to weaken as his emotions get the best of him. In front of the World Marshal Tower, Raiden is confronted by Desperado operatives Jetstream Sam and Monsoon, who chastise him for not giving in to violence. Suddenly, Raiden uses his "Jack the Ripper" persona after being stabbed in the abdomen by a soldier to feel legitimate pain. The adrenaline turns him into a psychopath bent on killing Monsoon, which he eventually does.

If you're keeping track, Raiden went from honor-bound swordsman to emotional wreck to murderous psychopath in a matter of minutes.

@:

Did read the manga; because Kid has an even crazier character change.

As the story continues after the Baba Yaga Arc, Kid looks to find Eibon's greatest weapon. Instead of finding it, he is captured by Eibon, who is a villain in the manga, and placed in his greatest weapon, The Encyclopedia.

As the others try to save him by entering the Encyclopedia themselves, Kid is subject to complete symmetry, otherwise known as nothing. All sides, all angles, all views are symmetrical. It drives him insane and forces him to confront the fact the entire world is asymmetrical, driving him into insanity. When Black*Star catches up with him, it's too late. Kid has turned into a villain and wants nothing but the elimination of the planet.

My first thought was Yoko Nakajima from The Twelve Kingdoms. There’s amazing character development in that series, for her and several other characters.

@Koyuki11:

Because Tsuna's your favorite character, that just made him easier to think of in relation to the topic :) But yeah, great example.

And maybe they weren't drastic changes in personality, but goodness knows many of the villains in KHR! had an odd habit of becoming his allies. I mean, most, if not all of them, had this happen at some point (with even more in the manga considering that the story went further there).

Are we allowed to talk about video game characters here? I'm going to pretend that we are...

My suggestion would go to Luke fon Fabre from Tales of the Abyss (actually...now that I think about it, they did make the game into an anime, so this applies to the original prompt anyways! :D)

I mean, the kid starts out as an arrogant little brat with a serious case of hero worship. Then he develops an overblown sense of self-importance which ends up getting a lot of people killed. This leads to him lashing out at everyone and blaming them for his short comings. Then he's able to overcome it for a time to be the big dang hero. Then he goes through his (obnoxiously annoying) inferiority complex phase where he attempts to be the martyr. Finally, the game rounds out with him just maturing as a person and coming a long way from the brat we met in the opening.

Honestly, not only does he change a lot from start to finish, he also goes through half-a-dozen extremes before he finally manages to settle in a middle ground. For that reason, I feel like he grows a lot as a character. :)

@CelestialSushi:

Yeah, I was really trying to think of a good example and wasn't coming up with anything. Turned out that the answer was right in front of me. Or behind me, since that's where my manga is located.

I recommend Death Note, unless you really aren't into a series involving people dying of heart attacks left and right. I actually know very few people who DON'T like it. If you're wondering whether to start with the anime or the manga, it's really a toss-up. They are nearly identical, save for the last episode/last couple chapters. The conclusion in the manga works so much better, even though it's the same basic outcome. That's my thinking, though.

I'd say Obito Uchiha from Naruto. As a kid he was emotional, weak, not very smart, and kind hearted. But when he grew up he became powerful, cold, ruthless, and intelligent. His personality did a total 180.
And he went from a seemingly incidental good guy to the main villain.

Watanuki from xxxHolic . First he was childish, silly, over dramatic then becomes serious his personality takes a dramatic change during the end of the series.

I think Saya from High School of the Dead changed dramatically. She went from a stuck up and girly, to a bamf in just 12 episodes.

I recently acquired a copy of Spirited Away, and while rewatching it I really noticed that there is a lot of character development for Chihiro. Over the course of the movie, she goes from a scared little girl to one who can use her wits and stand up against her fears and win back her parents. I guess working in a bathhouse for spirits does that to ya. :P

My guess would be when Riku first transformed into Ansem.
That was a dramatic change...Didn't see that coming.

@Keba Si Rota:

Whoa... never read Death Note (I'm vaguely familiar with the overall plot), but to me, that example knocks it out of the park :D Somehow, I had forgotten that drastic character changes also include going from good to bad rather than just from bad to good.

I wouldn't say that this is THE most dramatic change, but I gotta vote for Light from Death Note. He starts off as a young man with a bright future. Then he finds the Death Note. When he uses it to kill a criminal for the first time, he freaks out. It's not long before he decides to purge the world of criminals, using the Death Note without a second thought. He even experiments with the Death Note, trying to control people before they die. As the story goes on, Light becomes more and more drunk on power, using people without a second thought, and killing off those who stand in his way.

If you think about it, as Light becomes more corrupt, his physical appearance changes. You can see it in his eyes. This is most noticeable when (SPOILER!) he voluntarily gives up his memories of the Death Note in the middle of the series. In an instant, he reverts back to the innocent person he once was. Then, when he regains his memories, you can physically see the transformation in his face.

Now that I think about it, he goes through multiple dramatic changes from innocent to killer, back to innocent, then back to killer again.

Naturally, people should expect spoilers ^_^ If we're talking drastic change, I just saw that last night while watching Toriko o_o And it scared the crap out of more than one person, I can assure you. I was NOT expecting Livebearer to help Komatsu with the Meteor Garlic... in fact, they painted it like he was still the crazed psychopath after Komatsu's memories and knowledge. But no, watching Komatsu's passion for the food and ingredients actually helped him re-examine his relationship with food, as he is a chef, after all.

I don't know if I should leave that in spoiler tags or not, so unless I'm given the okay, I'll just leave this post as is.

Another one I thought of was the Witch of the Waste from Howl's Moving Castle. If you've seen the film, you'll know it's not just a change in temperament, but also appearance O_o