Revelation 9:11

Their king is the (leading) angel of the abyss. This is further confirmation that the locusts represent demons. The names "Abaddon" in Hebrew and "Apollyon" in Greek both mean "destroyer." Only the Apostle John supplied information bilingually in the New Testament (cf. John 1:38; John 1:42; John 4:25; John 6:1; John 9:7; John 11:16; John 19:13; John 19:17; John 19:20; John 20:16; Revelation 1:7; Revelation 3:14; Revelation 12:9). The objective of these demons is to destroy people. God grants this lead creature permission here to carry out his objective against unbelievers as part of God’s outpouring of wrath on earth-dwellers (cf. Job 2:6). Probably we should identify this angel as one of the hierarchy of fallen angels that emerges from the abyss with the other demons (cf. Ephesians 6:12). [Note: Thomas, Revelation 8-22, pp. 38-39.] The revelation of his name simply expresses his objective. Identifying him as Satan is tempting. [Note: Walvoord, The Revelation . . ., p. 163; Smith, A Revelation . . ., p. 145.] But the text only calls him an angel. The appearance of Satan later (Revelation 12:3; Revelation 12:9) is much more dramatic than the introduction of this angel.