Located at the right bank of downstream Tamsui River, Tamsui has been an important port town in northern Taiwan since the 17th century. During the Qianlong reign, ethnic-Han settlements dominated downtown Tamsui. With the development of markets and streets, immigrant groups from different regions established their separate temples. The Fuyou Temple became the largest and most important cult center. Circumstances changed after the Sino-French War. During the war, French troops took the economically and strategically important Tamsui as the major battleground. In this local society, which had rarely been attacked by large-scale military force before, the new ways of battle-fighting and the French marine’s siege of Taiwan Strait affected the residents’ daily lives and economic activities. To cope with these circumstances, residents found their solace in popular belief. The locals constructed oral legends mixed with historical facts that attribute success of battles to the help of certain deities. A particularly notable example is the elevated status of Master Clear Water (Qingshui Zushi). Legends that feature deities who helped with military actions since early Qing dynasty indicate the regime’s intention to defend its legitimacy. The imperial plaque bestowed by Emperor Guangxu, in particular, enhanced the marvelous aspect of local legends. In this study, I analyze the narratives regarding Master Clear Water’s dropping his nose and his help with various battles, and investigate the development of Master Clear Water’s cult, as well as the factors contributing to the re-construction of cult in late Qing Tamsui local society.