According to one literary source (
http://nijia.prohosting.com/Temple/fan_fiction/rai/story1/measures1.htm) Beelia appears to be Satan's dog or henchman.
...Satan sits at his throne. His blazing with fire and anger fills his soul. Sin Chi has betrayed him and let Rai loose...He looks at his son Rennin who is standing before him and his new chief general, the old vampire, Psyche. Satan beings to tap on of his long finger nails on the arm of his throne. "Where are they?" growls Satan to his son."I had Vengeance and *Beelia* go get them," states Rennin....