Yeah. They have to be pirate ninjas. Ninjas can very well become pirates: Anybody who sails the sea robbing other ships is a pirate. But if one is originally a pirate, it would require unlikely discipline to become a ninja. Fullblooded pirates aren't very famous of their disciplinal tendencies.

We saw this arc seems to have animation of higher quality than the previous few. What do you think: Will the animation stay at this level for the rest of the arc, or is it possible it would fall in the middle of it? And is the quality of the animation tied to the quality of the script. I'm not saying Kishimoto would be behind the plot; that'd be quite improbable if not impossible, I suppose, but it would seem somehow intelligent that if they invested more into the animation, they would have also invested more into the story.