Shava

Shava is the mermaid who helped a knight named Wars to found the city.  It is named after both of them, Warshawa (pronounced Varshavah, 'w' makes a v sound).  The legend goes that after she was captured by a fisherman, she pleaded with the people of the town to help her, and pledged to always defend them if they did.  So, they rescued her.  She is usually depicted with a sword and/or shield to show that she defends the city.