The final order of created celestial beings.
Their name indicates; "high" "mighty" "burning" "exalted" or "brilliant".
They are described in the Book of Isaiah as having three pairs of wings. Two covering their faces, two are covering their feet and two to fly with. They seem to resemble a human figure since they have a face, voice, feet, and hands.
Their occupation is twofold -- to celebrate the praises and worship of God and to act as a form of mediation between heaven and earth.
From their antiphonal chant ("one called out to another"), we may conceive them to have been ranged in opposite rows on each side of the throne.