Daredevil began life as a joking, free-wheeling hero who once chided Spider-Man for taking things too seriously; he even had a second secret identity, a supposed twin brother named Michael Murdock that allowed him to step out from boring ol’ Matt Murdock’s life. Then Frank Miller came along …
Wesley Wyndam-Pryce. (That spelling looks wonky, but I got it from IMDB.)
Yeah, Wes changed a lot, but I think that was largely just character development over six years.
The Saint and the Cisco Kid started out as unrepentant criminals–Cisco, a character in an O. Henry short story, was a Mexican border thug who killed his own girlfriend to spite a gringo soldier. The Saint was a gentleman thief, likeable but not heroic. Both eventually became adventure heroes.
Nosferatu are a different tradition than vampires. Murnau’s Nosferatu changed a lot of small details, but was an unauthorized adaptation of Stoker’s novel, which is why his widow sued and all the copies were supposed to have been destroyed. We got lucky that some of them survived somehow.
Check out very early Homer Simpson. I would call growing dumber by the second character development.
Would NOT call it character development. :smack:
Someday they’re gonna trust us enough to let us edit our posts. . .
I actually meant to mention Homer. And yes, he’s gotten stupider and infinitely weirder and crazier as the years have gone by. All of the Simpsons have changed, really. Most of them have gotten deeper and others have just evolved. Karl and Lenny are sort of a couple now, Smithers is gay instead of just a suckup, Moe is deeply depressed, etc.
As far as Dracula goes, you might as well ask how Stoker got from Vlad the Impaler to his character. 
Mickey Mouse also started off as a mischief maker - for example in Steamboat Willie he renders “Turkey in the Straw” by nursing sow’s teats like an accordion keyboard, and pulling a cat’s tail and swinging it around his head. In later cartoons he became an inconsequential secondary character and now, as far as I can tell, he’s no more than a bland corporate logo/theme park greeter.
Re Dracula
IIRC Stoker depicts him as dressing completely in black, and being pale in thin when hungry and blushed and bloated after feeding. His presence is frightening, disturbing and sometimes nauseating.
Marley23 has it right. Orlock looks like the vampire as walking corpse and the embodiment of plague. Nearly all the traditional vampire folklore describes them this way.
The novel Varney The Vampire Or The Feast Of Blood-A Romance Of Exciting Interest hinted at Varney sexually violating his victims. After Bela Lugosi played the Count on screen, the vampire became all about sex.
Re Frankenstein
In the original novel (Og how I hate it.), the monster is highly inteligent. By hiding and listening to conversations, he learns how to speak several languages. He also teaches himself how to read IIRC Latin, Greek, and German. Again, Universal studios changed the popular conception.
What are you saying, that you don’t think the word “wretched” should be used in EVERY single sentence in an entire novel? 
I had almost forgotten that the monster was very resourceful. I mean, aside from learning languages he managed to befriend a blind man and keep himself fed, which under the circumstances had to be pretty difficult.
Nah. One of the many science problems in the book is the fact that the monster requires very little food. A few handfuls of nuts, berries or roots every day will do just fine.
Lestat from Anne Rice’s vampire novels. The character started out in “Interview” as a penniless peasant with no concept of how to make or keep money, boorish, rude, inconsiderate, violent, cruel, wilfully destructive, manipulative and a cold blooded killer. He has no particular powers beyond slightly superhuman strength (he has to drag an empty coffin) and speed. He is so guileless that a group of slaves he feeds from manages to conspire against him for several months and he’s totally ignorant of the fact. He’s also almost as vulnerable as a human, a cut throat manages to ‘kill’ him for several weeks. He is also apparently dependent on his coffin to the extent tha he has to drag it from a burning house and beg the neighbours to take him in.
By the second book he’s an aristcocrat with a huge personal fortune. He’s witty, charming, seductive, a connoisseur of fine art. He can fly. He can read the thoughts of all people around him and especially those people thinking about him and the people he feeds off. He is virtually invulnerable to normal damage. At the beginning he gets shot and immediately heals all damage while and by the end of the book he can’t be killed by any means. He knows how to sleep in the ground and has done so numerous times and hasn’t slept in a coffin since the first few months after he was made. He’s a noble soul and will only feed on criminals.
The two characters share no similarities beyond the name and speaking French. All this is casually glossed over as “oh all those people I killed really criminals” when he was noted to feed on children and exterminate entirely families for fun. No explanation was ever given for his change in powers, sleeping arrangements wealth etc.
What do you expect? He is French after all! 
I can’t believe nobody’s mentioned Hannibal Lecter. He started out as a complete sociopath, brilliant but animalistic who killed anybody without provocation or remorse and took pleasure in their suffering. By the time of Hannibal he’s become more James Bond than Albert Fish, killing people "who need killin’ " and underneath it all a wounded widdle boy (though still brilliant but animalistic).
The Sandman was completely totally redone by Gaiman into something that had a name only relationship to the original.
In the Bible G_d begins as a primal force with a seriously out-of-control anxiety and mood disorder but becomes some sort of loving nature spirit.
Also on MAS*H, Margaret goes from an adulterous psycho-bitch to a woman of great compassion and integrity. Though this took years in the series, remember that in “reality” this and Hawkeye’s transformation would have occurred in a matter of months if not weeks since the 11 years of the series covered only the last 2 years of the Korean War.
The Wicked Witch of the West, of course, became the subject of a revisionist novel and musical in which she’s the good guy (and picks up the name Elphaba as an homage to L. Frank Baum).
The movie version of Forrest Gump has next to nothing in common with his literary alterego other than both were U. of AL football champs of limited intellect.
The character of Edith Bunker changed radically from the cynical but not so stupid pantsuit wearing character of the first few episodes to the e’er ebullient hausfrau dingbat of the last 32 seasons. George Jefferson likewise went from a sharptongued and sharper witted ambitious businessman to a stumbling moron who was always the butt of other people’s jokes.
In the fiction of the dread Anne Rice there have been several transformations, most notably that Lestat and Armand somewhere along the line became good guys rather than literally cold-blooded murderers. Also, Armand changed from the auburn haired eternal adolescent of the books to the horsemaned Antonio Banderas of the movie.
I don’t think this falls under the OP’s category. Morpheus wasn’t an alteration of the gas-masked JSA member, or the red and yellow spandex-clad dream guardian. They just happen to have the same name.
I once read a very old Popeye comic strip in which he plays craps against the Sea Hag to get his ship back. That kind of thing didn’t even happen in the early cartoons.
Tentacle Monster I don’t know if that’s a change as much as simplification. Thimble Theater (the strip title was changed to Popeye later) had a rich detailed world. It was impossible to convey all that in a few minutes of animation. So they focused on Popeye, Bluto, Olive Oil, and Spinach.
Don Quijote (pipes in the graduate student) - he went from being a dumb, pathetic character (I still find the first couple chapters terribly sad for their tragic cynicism) to being a sympathetic hero - deluded, yes, but more honest and noble than most of the people he meets.
James Bond
Go read Casino Royale. It is hardly Sean Connery material.