Oooh yeah. There've been a few like that for me, but it was most recently Midna. I initially was concepting Midna as a far more smug and sassy kind of character in terms of her personality. But as I worked on her design further and decided to have her try and lean more into the spiritual roots of her family, that personality type stopped to feel fitting since her background had essentially shifted.

That would be Ichigo for myself! She was initially designed while looking into making a Magical Girl character. In the end she filled the role of a Maid Club member with dreams of being part of an Idol group, eventually becoming taking the role of the Head maid of the Empire Club. So quite a different life to being a pure light and a fighting force for good!

Several. A big one actually being the Olivux regional grand champion, Foley. In time his development and general foil/role had changed dramatically, especially to fit better with the general tale being told.

Elio was supposed to have a small family composing of him and his grandfather who ran an antique shop in the city.

Grim was supposed to be a Pokemon professor in training-
And Blake was supposed to be very prickly and mean instead of his current very laid back and friendly self

Two of my most recent OCs: Sabi and Icebella. Their current personalities and roles actually were switched around when once I had the idea of turning Sabi into more of a family woman, moving the original more colder personality to Icebella, while also switching their jobs as well.

Ruth was going to be a dude.

Hmmm, I’ve definitely had characters develop in ways I didn’t anticipate.

Heather was initially NOT going to be an Elite 4. In fact she was supposed to end up moving over to a contest starlet after her league run.

Lex was also supposed to be the Champion until I came up with Lionel.

So, nothing too crazy, but different developments for each of them nonetheless. I have more extreme cases of this for my Visual Novel: The Nameless Braves, but I can go into that another time haha

Paleni actually was originally this sweet, mom friend of a Witch before she turned into whatever type of menace people are going to see her as.

Yet to get a design for her, but I have a character in the works called Rosemary.

Originally, she was just meant to be kind of a kooky, spacey doctor side-character.

Now, she's still a doctor. But she's downright despicable/major villain tier