All life which is not born of the Yaevre directly came from the Avehr. When Adwar Mael Khama happened, the power of the yaevre was bound to the lands, warping it, and the Avehran kinds which dwelt there, into terrible things. Much of the first age of Czarn was spent fighting off these terrible Avehrkin, who were beyond the words mighty and terrible in strength. Throughout the next 5 ages, the Avehr of the land and air became more domesticated, with the children of the Yaevre learning how to overcome them.
However, in areas beyond the children of the Yaevre's reach, these mighty and terrible Avehr from the first age still dwell and thrive, the biggest place being the seas.
Because of the Avehrkin's territorial hostility towards each other and Yaevre-children, seafaring was at first a very dangerous trade. The orcs first invented it to gain passage to the mainland, and ages after, the most daring among man began to give it a hand.
The Conglomeration perfected the work, however. After their initial conflicts with the Hudorians settled down, they began to enlist them as precious and privileged scouts of the water, using their inherent ability to sing and calm Avehr to give their ships safe passage. These 'underscouts' were highly paid and became a dire commodity for international trade.
Conglomeration ships took other measures against these Avehr however. Many ships' hulls are lined with meshes of teeth, crafted from Aeqbane metals. Between measures like these, and the heavy presence of underscouts, most of the Mouth of the Sea has become a much safer stage for international trade.