Father Kelly in his conversation with Lochley mentions "seraphim." A "seraph" or its plural "seraphim" is one of a class of celestial beings mentioned in Old Testament. They may have human form, can be referred to as "angels," and are mentioned in the book of Isaiah as winged guardians of God's throne.
"... I saw the Lord sitting upon a throne, high and lifted up; and His train filled the Hekhal. Above Him stood the Seraphim; each had six wings: with two he covered his face, and with two he covered his feet, and with two he flew."