Clever fishers will often latch onto one of these wavekin and use its extraordinary propulsion to pull their ships. Once it grows tired, they can repay its kindness by hauling it out of the water and eating it.
The tremendous speed at which this manta glides along can only be explained by arcane enhancement. The prevailing theory suggests some manner of adaptation in its gills which allows the wavekin to convert the aetherial current into a preternatural propulsive force.