These are demonic spirits that perform signs and go out to all the kings of the earth, to assemble them for battle on the great day of God the Almighty.
Textus Receptus (TR) - Revelation 16:14 >εἰσὶ γὰρ πνεύματα δαιμόνων ποιοῦντα σημεῖα, ἃ ἐκπορεύεται ἐπὶ τοὺς βασιλεῖς τῆς γῆς καὶ τῆς οἰκουμένης ὅλης, συναγαγεῖν αὐτοὺς εἰς πόλεμον τῆς ἡμέρας ἐκείνης τῆς μεγάλης τοῦ Θεοῦ τοῦ παντοκράτορος —