'Mighty Angel' in the Bible

And I saw mighty angel proclaiming with a loud voice, Who is worthy to open the book, and to break the seals thereon?

AND I saw another mighty angel descending from heaven, clothed with a cloud; and a rainbow on his head, and his countenance as the sun, and his feet as pillars of fire:

And a mighty angel took up a stone as a great milestone, and cast it into the sea, saying, So with rapidity shall the great city Babylon be hurled into the deep, and never shall be found more.