Shiva Purana
षण्मुखश्शिवसम्भूतः शक्तिवज्रधरः प्रभुः ॥ अग्नेश्च तनयो देवो ह्यपर्णातनयः पुनः ॥ ७० ॥
He is the six-faced Lord born of Lord Śiva and holds the thunderbolt of power. The son of Agni was Deva and he was again the son of Aparna.
english translation
SaNmukhazzivasambhUtaH zaktivajradharaH prabhuH ॥ agnezca tanayo devo hyaparNAtanayaH punaH ॥ 70 ॥
hk transliteration by Sanscript