Command water spirits was a spell unique to Zakhara, the Land of Fate.
This spell did not actually allow the caster to command water spirits, instead it allowed them to manipulate the currents of large bodies of water to move objects on or under the surface.
This spell was particularly useful for controlling ships in becalmed water or during a severe storm.
The caster could also use this spell to create a powerful undertow to drown his enemies.
This spell required a clear glass to cast.