Based on the series of attacks just now, Akrawa believes that even if the opponent has some casting ability, it's unlikely they have reached the level of an Official Wizard.
The reason is simple: there are many ways to counter Divination Art, such as super-tier rituals, highly mysterious Extraordinary Items, and spells that disrupt Spirit Realm information.
Even ordinary people with the help of certain Protective Talismans can manage it.
As for the straightforward attack methods, although the "Voodoo Potion" is very effective, Official Wizards have many more sophisticated means and aren't easily countered by one's spells.
Even with a good number of sailors, a single Wizard Apprentice aided by Kara Wusu could kill them all, showing the dominance of the Extraordinary on the battlefield!
It's just uncertain how capable the captain of the warship, which surely belongs to the Official Knight level, would be?