Satan

“He that committeth sin is of the devil; for the devil sinneth from the beginning.  For this purpose the Son of God was manifested, that he might destroy the works of the devil” (1 Jn 3:8).

“Ye are of your father the devil, and the lusts of your father ye will do.  He was a murderer from the beginning, and abode not in the truth, because there is no truth in him.  When he speaketh a lie, he speaketh of his own: for he is a liar, and the father of it” (Jn 8:44).

“…Beelzebub the prince of the devils” (Matt 12:24).

“Wherein in time past ye walked according to the course of this world, according to the prince of the power of the air, the spirit that now worketh in the children of disobedience” (Eph 2:2).

“Be sober, be vigilant; because your adversary the devil, as a roaring lion, walketh about, seeking whom he may devour” (1 Pet 5:8).