'Mighty Angel' in the Bible

and I saw a mighty angel who was proclaiming in a loud voice-- 'Who is worthy to open the book and break its seals?'

Then I saw another mighty angel, descending from Heaven. His robe was a cloud; over his head was the rainbow; his face was like the sun, and his feet like pillars of fire;

Then a mighty angel took up a stone like a great millstone, and threw it into the sea, crying-- 'So shall Babylon, the Great City, be violently overthrown, never more to be seen.