Skandapurana 1.4.28.46

1.4.28.46

yamaḥ prādādanucarau yamakālopamau tadā..
unmāthaṃ ca pramāthaṃ ca mahāvīryau mahādyutī.. 30.46 ..

Then Yama gave two attendants resembling Yama and death: / Unmātha and Pramātha, of great prowess and great splendor;