Unohana goes from being the most bloodthirsty, sadistic warrior in the Soul Society to being a kind, motherly person who goes out of her way to heal and help others, even enemies, and who tries to avoid and prevent fights. Is this all an act?
I understand she was waiting around for Zaraki, but she could have done that without becoming the equivalent of Mother Teresa. Did she really have a change of heart about others, and if so, why?
Unohana was the First Kenpachi several members of the 11th Division fear her, and so do a few of her fellow captains, according to the former captains of the 5th and 7th Divisions.
No captain wants to get on her 'Bad Side' as -
Spoiler -
Retsu Unohana (卯ノ花 烈, Unohana Retsu), formerly known as Yachiru Unohana (卯ノ花 八千流, Unohana Yachiru), was the captain of the Fourth Division in the Gotei 13. She was one of the oldest and most experienced captains, and was the Soul Society's best healer, as well as the first person to wield the name Kenpachi.[2] Her lieutenant was Isane Kotetsu.
source - http://bleach.wikia.com/wiki/Retsu_Unohana
And there's no information to be found about wether or not she's faking her compassion, however I was able to find -
Spoiler Alert -
However, after the revelation of her past as the first Kenpachi and Shunsui Kyōraku calling on her to draw on her experience from then, Unohana's personality reverts to her original violent and bloodthirsty nature; once she meets with Kenpachi Zaraki, she comments how the scar left on her chest was causing her pain just from the sound of his voice.
Emphasis is mine, source - http://bleach.wikia.com/wiki/Retsu_Unohana
Some point in the past, she named herself Yachiru Unohana[13] and was known as the most diabolical criminal to ever exist in Soul Society.[14] Genryūsai Shigekuni Yamamoto sought her out and she joined him, becoming one of the founding members of the Gotei 13. Unohana laid the foundations of what would be known as the 11th Division and became its first captain, as well as the first Kenpachi. At some point in the past, Unohana was taught medical techniques by Tenjirō Kirinji as a way of prolonging fights
source - http://bleach.wikia.com/wiki/Retsu_Unohana
The quotes above would indicate that, somehow she has had a change of heart after joining the Gotei 13 & founding the 11th Division, but somehow still shows her more menacing side.
