Legal consequences are important to mention, especially in regions where downloading from torrents is against the law. Even if the user isn't aware, it's good to provide a warning.

Let me structure this: start with an introduction about the arc's popularity, then move to legal ways, then alternative methods, risks involved, and a conclusion pushing for supporting creators. Each section with clear headings and bullet points for readability.

They might want details on the number of episodes. Let me confirm: the arc has around 77 episodes, right? Split into two parts. Including that could help the user know how much content they're downloading.

Wait, the user specified a long piece, so maybe elaborate each point more. For example, in legal sources, explain subscription models, how to download, and maybe the device compatibility. For torrents, mention site examples but without linking them directly, as that could be against policies.

The user might also be interested in why the Whole Cake Island arc is popular. Briefly talking about the arc's significance could add value. It's a major part of the story leading up to Wano Country and the final saga, so highlighting that might be useful.

Also, maybe include tips on verifying the legitimacy of download sources to avoid scams. Suggesting trusted platforms again.