Hisen (飛仙, Flying Sage)[1] is a kind of Sennin which does not serve a ruler. They are listed upon the Divine Registry of a kingdom, though they are not required to serve a kingdom's ruler in anyway in contrast to Grounded Sages.
Hisen are not granted their immortal status by a ruler either. For instance, all the sages and oracles who serve on the Five Mountains ascend to sagehood on their own power and achievements. These sages are also accorded the rank of "Count" and have sufficient rank and power to cross the Void Sea.