The Moerani were, according to the Second Doctor, a species that lived outside of normal existence in a dimension called hypertime.
Kemen lured a young Moerani to Earth and used it to attempt to create a utopia on Earth. Instead, a time storm engulfed most of the Earth. The Moerani helped the Doctor repair the damage done by Kemen and then committed suicide. The other Moerani came to Earth to take its body. (PROSE: Across Silent Seas)