Nothing much about its origin is explained.
Hon exists to harmonize the relationship between Humans and Anothers. Their primary job is to assist and protect Anothers who wish to live harmoniously with human beings. They also prevent them from harming humans and also prevent human beings from harming Anothers.
Hon hides the existence of Anothers from ordinary human beings. It erases all the trases of damage caused by Anothers. Hon's leader Su JIn Ji is the the key to open the Pandora's Box which is what Atran is after.