The ship that Allan and Nathaniel had hired was a pirate owned Caravel , the only means of crossing the dead zone of the Southern sea.
This had all been an unplanned detour , their main job being to only collect the taxes from the human oasis on the main continent.
But when they got word of an island that was rumored to have a Nameless Death , they could not resist the chance to seek glory and favour from their Beast Lord for capturing such a fine specimen for his collection.
They also learned that the island had formerly been used as a mine for Almond stones, meaning that it was a verified habitable zone.
In Praiyas , unless one was a monster with insane endurance , it was always good to verify how habitable a region was.