The affix ḍhak comes in the sense of 'this its deity' after the name agni,
Thus अग्निर्देवताऽस्य = आग्नेयोऽष्टकपालः ॥
Vart:- The affix 'dhak' always comes after the words Agni and Kali, in the various senses of the affixes called Pragdivyatiya. See 4.2.8.,