Based on the provided text, who was Damu Anna and what were the key facts about his life mentioned?

The source material in Chapter 25 identifies Damu Anna as a well-to-do Kasar (bronze-smith) from Ahmednagar. He is described as a great devotee who was devoted to Sai's feet. Two key facts are highlighted about his life. First, he was initially childless despite having two wives, but he was eventually "blessed with sons" through Sai Baba's grace. Second, he had a regular vow for the annual Ram Navami festival in Shirdi, where he would provide one of the two large flags for the procession, an act he performed for many years with unwavering devotion.