The Totmess could be called a parasite, but they themselves prefer to say they are a symbiotic existence.
They multiply by attaching part of their soul to others and growing into them, taking over the body. Otherwise look like the people they take over. Live to be as old as the host, but parts of their memories pass over to their progeny.
The bodies they take over are unable to reproduce normally and their organs slowly shift - new ones appearing and old one atrophying.
They tend to try to get into positions of political power. Most totmess don't hide their race, seeing it as unnecessary.
Often, when approaching the end of their life they seek out a host or hosts to graft their souls to, wanting to leave something behind. While most look for volunteers or people who would sell their children, some turn to kidnapping or forceful grafting. Despite these practices, due to many years of cultural indoctrination most people find this practice acceptable.