Isaiah 27:1

Leviathan : a twisting aquatic monster, possibly the crocodile of the Nile, and used symbolically of Assyria and Babylonia (by the twisting Euphrates River IBD).

Revelation 12:9

Satan : a person, male (evil angelic),an angel that has rebelled against God

Revelation 20:1-2

Satan : a person, male (evil angelic),an angel that has rebelled against God