Filler? are you kidding me?
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I understand you do not like Yamato as a character in terms her being a fangirl of oden. But come on man in comparison to Carrot through this arc what did she do? All right saving Marco's life, teaming up with nami taking down one of big mom's homies and her tag teaming with Wanda against perospero which ends up being skip over in comparison to the strawhats and their alliance. We did not get any new revelation from her character regarding her relationship/history with pedro or about the dawn he spoke of in an earlier arc. Carrot just stood there when cat viper was down when the moon was covered. She has not anything since.
Yamato, we got to know little bit about her. Not just about her devil fruit, but we got to know she had conqueror's haki ever since she was a kid. Her reason behind why she wants to fight for samurai and a little bit of her relationship with her father. We got to know that her goal had not change even back than when she was a kid. Towards the end of the fight, we got to know what Kaido and Yamato race our. It was said, by marco previously Kaido confirms to us. There is still mystery regarding the significant about them. Even after the fight was over, she was still active throughout this raid. She was trying Freezing the bombs the best she could. Lastly encouraging momo not wuss out by himself and throw his life way. Instead let us fight together and die together if Luffy were to fall.