Final answer:
The information provided does not specifically address Norse beliefs about the aftermath of their gods' defeat; however, according to Norse mythology, the world would be reborn after the great battle of Ragnarök.
Step-by-step explanation:
The Norsemen, also known as Vikings, had a complex set of beliefs surrounding their gods, such as Odin, and the afterlife. While the provided information delves into Zoroastrianism and its concepts of good and evil as personified by Ahura Mazda and Angra Mainu, it does not directly address what the Norsemen believed would happen after Odin and the other gods were defeated by evil. According to Norse mythology, specifically in the tales surrounding Ragnarök, the Norsemen believed that the world would end in a great battle where many of the gods would die. Eventually, a new world would be reborn from the ashes of the old. However, without additional context or an explicit connection to Norse beliefs in the information provided, a direct answer about the Norsemen's beliefs after the defeat of their gods cannot be conclusively given.