Revelation 16:10

τὸν θρόνον. The throne: the word is best taken quite literally, not in the vague sense of his capital, the “seat” of his empire.

ἐγένετο ἡ βασιλεία αὐτοῦ ἐσκοτωμένη. Was his throne the light thereof (Isaiah 50:10-11), as God and the Lamb will be of the new Jerusalem, in whose light the nations will walk? Cf. on the whole plague Exodus 10:21, ch. Revelation 9:2.

ἐκ τοῦ πόνου. The darkness was of itself distressing, and deprived them of such distractions from pain as they had before. It is clear from the next verse that the seven last plagues are more terrible than even the woes, for of these we are told that each passes before the next comes, while each of the last plagues continues till the end.