The answer is actually quite simple.
Their ship was rammed and sunk.
In the Southern Sea, there are many reasons why a ship could sink.
For example, encountering a storm, facing chaotic ocean currents, or due to poor management by the crew...
But if the ship was rammed and sunk, then there's only one possibility.
They encountered a magical beast attack.
"Damn it!"
During the meeting on how to attack Ian, the representative of the Canaan Moore Dragon Worship Cult, an elf with light silver hair, angrily slammed the table: "If it weren't for that damned Iron Armor Shark ramming and sinking my ship… I could have even deployed the sniper magic conductor for a long-range kill!"
"And now, we're forced to look for an opportunity to strike head-on."
Saying this, the elf gritted his teeth in fury: "My ship... my reinforcements... my funding..."
