Weapons change?

I was fighting Pop in the Battle Arena. I won And I was able where weapons to use, I saw a different weapon. It was a sword instead of the Addow dagger. And the Staff of the Unidy fairy looked different. Is this possible? Can your weapon change? BY the way I have 5 weapons I can carry only 5 And I am hoping to get a better weapon than my twig sword. Is there way to unequip a weapon from your pet?