The Bloody Baron's Blood Sea Hell skill was extremely powerful, not only did it have a wide range, but it also inflicted the same damage to every person within the blood sea.
In other words, whether it was one person or a hundred, a thousand, being in the blood sea meant being constantly subjected to damage. Once the blood sea became too overwhelming, everyone would be directly devoured and killed by it.
This move was very potent but could be easily countered by forces that were directly opposed to it, like holy light, flames, and thunder which possessed attributes that could break through evil and cleanse.