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ZeniMax has trademarked "The Brigmore Witches" and "Void Walker’s Arsenal," both of which could be related to Dishonored.
The Brigmore Witches was referenced among Dishonored's plethora of literature. The Void Walker's Arsenal is a little more ambiguous. Corvo explored an area called The Void on a few occasions in Dishonored. It was where he met The Outsider, and often received new powers.
These new trademarks could very well have nothing to do with Dishonored. Alternatively though, it could be hints at upcoming DLC, or maybe even expanded projects based on the property.
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