大毘盧遮那成佛經疏 20.9

20.9

第六火神名為忿怒，即以此名義為真言等，如上也。其身烟色者，謂非甚黑非甚白，閉其一目（如不動尊也），其髮散上如蓬頭之狀，作大吼形，謂狀如開口大呼吼狀也。口有四牙俱出，二上二下。此亦攝二事，一火、一風也。

The sixth fire deity is named Wrathful (Krodha), and his mantra and the like are derived from this name and meaning, as above. His body is smoke-colored, meaning neither very dark nor very pale. One of his eyes is closed (like the deity Acala), and his hair is disheveled and pointing upward like a tangled mane. He assumes the form of roaring loudly, which means an appearance like opening the mouth wide and roaring loudly. Four fangs protrude from his mouth, two above and two below. This also encompasses two elements: one is fire, and one is wind.