Seraphim

"The Glowing ones" == 'Those who kindle / make hot' [1]

Of the highest angelic class, caretakers of god's throne. Sentient but too divine and knowledgeable for a human soul and even most of the angels to communicate with. They can speak to others if they so choose but don't have much of a personality due to their enamorment with God.

Perpetual & undying passion for God and praising him w/ a firey passion and wholly purifying others by a burning and all-consuming flame with a radiant and enlightening power, dispelling and destroying shadows of darkness [1].

Purification of Souls: Following illumination (Cherubim) and purification (Thrones), Seraphim have the function of instilling a passion and love. parent: Holy Angels, Angels

ref angelolgy

[1] The Celestial Hierarchies [ref]