Population Migration / Travel
Rebellious Ak'thri clans resisting control of the growing priesthood of biomancers escape their power by becoming sea nomads, adapting themselves to a permanent life on the sea and become the nagathi.
The excultid people of Kalmasa experience a fundamental split. Over the centuries, the knowledge of the biomantic arts gained by the Ak'thri from the ulan spreads with their growing power throughout Kalmasa. A priesthood develops that guards the knowledge and use of these arts. The more traditional Ak'thri villages resist this attempt at control over what they see as their birthright.
Unable to resist the growing might of this priesthood, they use their arts to adapt to life at sea, becoming sea nomads. Over generations, they adapt to this aquatic environment and become amphibious. They establish their villages on massive rafts connected together to which the mobile tanep kelp is grafted. Their biomancers strengthen the natural tanep kelp's ability to swim across the surface by means of flagella, growing these flagalla and learn to direct the tanep's movement by their will.
These people, the nagathi, become increasingly detached from the land and escape the ships of the tecuhtli by fleeing inwards into the windless expanse of the inner Torvalen Sea. The tanep powering their rafts gradually grows over the structures completely until they find themselves living on giant mats of the kelp. Their biomancers further develop the tanep, encouraging it to grow a rigid matrix, eliminating the need for wooden structures and enabling new villages to simply bud from older mats as well as grow dwellings on its surface.
The nagathi develop an abiding hatred for land peoples and begin to see them as mere prey and sport. They wreak an eternal revenge on the land by raiding and murdering coastal villages along all the coasts of the Torvalen sea, retreating always to their windless fastness in the center of the sea. The ulan amas, realizing that the ulan bore some responsibility in these events, gradually withdraw from the affairs of the surface peoples and do what they can to foil the nagathi predations and so became yet another enemy of the nagathi.