She was one of the reasons that I kept watching this bizarre anime called Seikon no Qwaser. (and the other reason was the shota named Sasha)
It can be worse in fan service than "Queen's Blade".
I don't recommend Seikon No Qwaser. I just kept watching until until the end because I though: "This is so bizarre that I want to see what the hell will happen with the plot"
(plot, what plot?)
But anyway, Ekaterina is a fun character.
She is the kind of lolita that is a trap (no, that doesn't mean she is a boy).
She just tricks you when she pretends to be a sweet girl, and then reveal her true personality and kick your ass. And Hana is her poor victim.
This is the kind of girl character I usually like (usually I dislike dumb girls that are just made of moeblob and don't have any personality)
Thanks a lot for the comments! ^_^