As they say in Japan - Men come first, Women come second.
When you watch series like this, then you really have to turn off your American eyes. It's quite easy to take the American views to some of these series and question it. Often times, I fail to do so. This is in particular when fighting series that include female fighters. Many such characters have prominent roles; but eventually, they get "shoved to the side" in favor of a dominant male character.