Determining the most watched anime can be subjective and vary depending on different sources and criteria. However, here are some anime series that have gained significant popularity and are often considered among the most watched:

• "Naruto" and its sequel "Naruto: Shippuden"
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• "One Piece"
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• "Attack on Titan"
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• "Dragon Ball" series (including "Dragon Ball," "Dragon Ball Z," and "Dragon Ball Super")
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• "Death Note"
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• "Fullmetal Alchemist: Brotherhood"
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• "My Hero Academia"
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• "Hunter x Hunter"
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• "Bleach"
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• "Fairy Tail"

It's important to note that viewership can vary depending on factors such as release date, accessibility, and geographic region. Additionally, new anime series are continuously being released, and popularity can change over time.