Historically, this Cyrus was 'called' and 'chosen', as God even surnamed him, much as He did Isaac, John the Baptist, etc.  In other words, these were named by God Himself, and 'chosen', for His Plan. God also surnamed others, such as Loammi, Jezreel, and the children back in Isaiah 8, but the purpose was contrary to that of Cyrus, and there's the difference. Cyrus helped pave the way to re-establish God's Temple at Jerusalem, even restoring the Temple instruments that Nebuchadnezzar had taken to Babylon. God would even call Cyrus 'His anointed' in...

 

Isa.45: God brings calamity about as the inevitable consequence of sin. Cyrus raised up by God.

     There's a good work called Dan :The Pioneer of Israel, which points out that this Cyrus and God's 'mighty ones' may have been scattered ones of the 'lost' Israelite tribe of Dan, which some migrated to that area of Media just north from where the armies came to destroy Babylon. This may give more importance to the meaning of Cyrus being God's 'anointed' and these 'sanctified ones'.¹

 

Isa 13:4   The noise of a multitude in the mountains, like as of a great people; a tumultuous noise of the kingdoms of nations gathered together: the LORD of hosts mustereth the host of the battle.

     Again historically, this was Cyrus and the Medes under Darius, joined together against Babylon. The word 'nations' is 'gowy' in the Hebrew meaning 'a foreign nation, hence a Gentile' (Strong's no.1471). 
     The destruction coming upon the last world Babylon 'beast' system, which is but a type of the ancient Babylon, will be performed by God and His elect, as Cyrus more than likely was God's elect also, especially as it relates to our future (hint for the deeper student on what 'Anointed' means). But the destruction won't be done with weapons of man, but by The Holy Spirit. The future destruction of Babylon is already set; none can stop it, for God has ordained it. So don't worry about all the hype by some talk show hosts issuing a warning about the coming destruction. They're teaching to the enemies of God that His hand in this destruction is coming, as they haven't a correct clue of the 'signs' and events which God gives in His Word. But God's own do know, and just how, where, and even the 'season' to look for because Christ's coming 'as a thief in the night' will not surprise those who believe on Him and study His Word.

 

Isa 13:5   They come from a far country, from the end of heaven, even the LORD, and the weapons of His indignation, to destroy the whole land.

     This phrase 'from the end of heaven' points to our future, not Cyrus' time. So what are the 'weapons of His indignation' of the future? It is the 'wrath of The LORD.'

 

See Jer.50: 6 My People hath been lost sheep: their shepherds have caused them to go astray, they have turned them away on the mountains: they have gone from mountain to hill, they have forgotten their resting place. 17-20; 39 No more inhabited; (still future)

 

 So when will this happen? After Christ gathers His elect from the 'four corners of the earth', as we learned in the last two Chapters of Isaiah 11 & 12, and in Rev.6. This 'wrath' from God will be the seventh angel pouring his vial out upon the Babylonian beast system. It won't harm those who believe on Christ as Saviour and understand His Word, and thus are not deceived by the 'false messiah'.

 

Isa 13:6   Howl ye; for the day of the LORD is at hand; it shall come as destruction from the ALMIGHTY.

      Remember, this is towards Babylon, not God's People. It is to the sinner who doesn't care about