Rera is an Ainu word which means "wind". Ainu is one of the indigenous peoples in Hokkaido, northern island of Japan. Their culture, which is based on animism, is very different from Japanese culture. Unfortunately since Meiji Era most Ainu people merged into mainland Japanese and their heritage was almost lost. Recently both Ainu and non-Ainu Japanese are trying to restore Ainu unique culture, tradition and language. In this lyrics 獣道 literally means "animal trail" but can also be interpreted as "way which gods go", for Ainu people often regard wild lives as incarnated gods who give their flesh as a gift to human beings for sustenance. I translated this word as "unpaved path."