Three Girls Needed to Access Battle

[Mildcat]

I am trying to battle, but it says I need three girls to do so. I recently acquired Kelina, which gives me my third girl. It is still not letting me in. Is it a bug/glitch, or am I doing something wrong?

[natstar]

You have to click on battle then you select change team if it does not work click adventure and do the story a bit more since most players get their third harem member from the story which opens the arena part since it's after getting ankyo in the story that it tells you about the arena.

[Greetingz]

Its called progression in the story and unlock Red battler, Then  you can do battle.