He is very smart for his age, knows all about the events but has not told anyone the whole story. The power of remembrance gives him an advantage over all other unknowns. In version 0, he told of unknowns fighting and his mission to never let it happen again. Supporestly he works for Lena's father who wants to protect her from danger. Every unknown has made fun of his ears that looks like a elf, this is true but he denies being a elf.
He remembers everything from the very first unknown to the current unknown. It might be possible for him to even know the whole world and beyond. Noui does not want to share his knowledge but does appear when things have gotten worst. The rocks he carries is unclear to everyone, its also unclear if he even needs a magic rock for his powers.