Post a someone who's always trying to protect their Captain.

i guess isane is. She not only protects her captain but unohana retsu is like a mother to isane

Here. Izuru protecting Gin from Momo ^_^
I chose them because even after Gin's alleged betrayal, Izuru kept on thinking about his admired Captain.

I also wanted to post Momo defending Aizen. Because she didn't want to accept what he was in reality. And she kept on trusting in him and trying to bring him into the 'good side'. She was very loyal to him. So pity Aizen-sama is too evil. ^_^