In Norse legend, Ragnarok signifies the ultimate battle at the end of the world, where gods, humans, and monsters confront each other in a final conflict. It involves significant figures like Odin, Thor, and Loki, and culminates in widespread destruction, resulting in the death of many key gods and the submersion of the world in water. Following this cataclysm, a new world is believed to arise, emphasizing themes of renewal and the cyclical nature of existence in Norse mythology.