Source: The End of Eternity, pg(s). 83
Vannashiai is a resourceful miengu who watches over an underground oasis in Katapesh, known by the few that know of its existence as the Well Under the Blue Star. The Well was not always an underground oasis; Vannashiai once guarded the oasis when it was above ground and known by a different name before the arrival of the Drinkers of Tears, a pair of powerful shiras.
Vannashiai could neither hope to overcome the twin divs nor stop them despoiling her oasis, so she opened the earth and dropped the oasis into a cavern below. Vannashiai now protects a beautiful underground oasis that is safe from the shira and unknown to most passing travellers.