Mysterious waters are locations that look like a wreckage of a ship. They only appear when the Naval ExpeditionsImperial Decree is active. They contain either between 10.000 to 100.000 tier 3 or tier 4 Pirates or contain great rewards.
Warning: Unlike encounter camps attacking them does count as a real attack, meaning that if you put your shield off you cannot turn it on without recalling! You can attack them without shield though so it's likely a oversight.
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