post those characters who had very good character development

Jean Kirschtein from Attack on Titan

Shinichi Izumi from Parasyte: The Maxim. The way he develops is crazy

Gaara from Naruto/Shippuden~
He went from a crazy psychopathic killer to an honorable noble leader. <3

Keigo Atobe in Prince of Tennis. When he made his first appearance, he was a total jerk with no sympathy at all as he tried to break Tezuka's shoulder during their match. But as the series going on until now, he now has a better personality and not that selfish anymore. He's now being trusted as a respected leader and I respect him for that. :)

May

2003 Lust

Mikado ryugamine. I feel like he's going insane bit door bit and ITS AWESOME!!!!!! ye.

Yona

She still has a way to go, but she went from being a clueless princess to a badass fighter.

Seriously no one mentioned Kaneki

Rokuro Okajima AKA Rock from Black Lagoon. He starts out as a wimp and kind of boring, but he turns into a strategist and kind of a diplomat for the group. Then in season three... Hoo, did not think he was going to be that much of a badass.

Kyo Sohma from Fruits Basket <3 He went from being an a-hole to a kind person.

Levi Ackerman