20:2 And he laid hold on the dragon, that old serpent, which is the Devil, and Satan, and bound him a thousand years,
Other verses describe Satan as the destroyer going about upon the earth like a lion seeking those whom he can devour.
Revelation (of John) is part of the New Testament (although for a long time it was considered 'apocrypha'), so it is expected that Satan/devil shall be treated as one and the same, since this concept is introducted scripturally in the New Testament. Its roots, however, pre-date the NT and can be found in OT deuterocanonical (aka 'apocryphal') books and pseudoepigraphical books which are not part of the Phariaiscal Hebrew Old Testament, but are included in the Septuagint OT used by the Apostles.