ONL is an abbreviation of Obihiro National Laboratory. It is located just outside of Obihiro, Hokkaido. Many red eye researchers work here to understand devils and help them integrate better into society. Many devils are also kept on the premises for research purposes.
There is also an orphanage on the grounds referred to as ONLO (Obihiro National Laboratory Orphanage). Devil children who have lost their parents are sent here to be raised as well as hybrids born at the facility.