Satan
Satan is one of many titles given to the primary adversary of God and man. He is openly declared as such in the Bible (Job 1:6-7; Isa 14:12-17; 1Pe 5:8). God, in His sovereignty, has given Satan rulership of this present world, which will terminate at Christ's second advent (Eph 2:2; 2Co 4:4; Joh 12:31, 14:30; 16:11).