Broadly speaking, the Ten Kings are all commonly called King Yen-lo, but Yen-lo actually is king only of the fifth of the ten courts of hell--the others each have their own names.
廣義說來，十個殿的判官都稱為閻羅王；然各殿判官其實各有封號，唯有坐鎮第五殿的，才是「正宗」的閻王老爺。