(i) Sometimes it refers to men:

“And I have separated for thee destroyers, Each with his weapons, And they have cut down the choice of thy cedars, And have cast them on the fire.” (Jeremiah 22:7)

(ii) But at other times, it’s not so clear; Here are some verses where for the most part it suggests something ‘not human’ (and it’s usually ‘singular’):

“For the destroyer is coming against her, against Babylon, And her mighty men will be captured, Their bows are shattered; For the LORD is a God of recompense, He will fully repay.” (Jeremiah 51:56)

“The destroyer shall come upon every city, and no city shall escape; the valley shall perish, and the plain shall be destroyed, as the LORD has spoken.” (Jeremiah 48:8)

“For the LORD will pass through to smite the Egyptians; and when He sees the blood on the lintel and on the two doorposts, the LORD will pass over the door and will not allow the destroyer to come in to your houses to smite you.” (Exodus 12:23)

“And immediately an angel of the Lord struck him (king Herod) because he did not give God the glory, and he was eaten by worms and died.” (Acts 12:23)

(iii) The destroyer is the one who seems to have ‘wiped’ out the ancient peoples (of the ‘nations’) in the world, previously:

“The lion is come up from his thicket, and the destroyer of the nations is on his way; he is gone forth from his place to make thy land desolate; thy cities shall be laid waste, without an inhabitant.” (Jeremiah 4:7)

(iv) The destroyer is a ‘creation’ too, created by God Himself “to destroy”:

“Behold, I Myself have created the smith who blows the fire of coals And brings out a weapon for its work; And I have created the destroyer to destroy.” (Isaiah 54:16)

(v) The destroyer is called an ‘angel’ (as even mystical Judaism relates to this) —> and the Bible relates that there is ‘not’ one destroyer but ‘many’ destroying angels:

“He (God) sent upon them His burning anger, Fury and indignation and trouble, A band of destroying angels.” (Psalm 78:49)

(vi) Some of these ‘destruction’ had ‘numerous’ casualties in a very short span of time:

“Then it happened that night that the angel of the LORD went out and struck 185,000 in the camp of the Assyrians; and when men rose early in the morning, behold, all of them were dead.” (2 Kings 19:35)

(vii) At times, even Israel was ‘not’ spared of such massive amounts of deaths (in numbers —> God has “no” partiality) when they ‘sinned’ to that extent too:

“So the LORD sent a plague on Israel from that morning until the appointed time, and from Dan to Beer-sheba 70,000 men died.” (2 Samuel 24:15)

“When the angel stretched out his hand toward Jerusalem to destroy it, the LORD relented from the calamity and said to the angel who destroyed the people, “It is enough! Now relax your hand!” And the angel of the LORD was by the threshing floor of Araunah the Jebusite.” (2 Samuel 24:16)

(viii) ‘Grumbling’ caused some ancient people to be ‘slayed’ by the destroyer too:

“Nor grumble, as some of them did, and were destroyed by the destroyer.” (1 Corinthians 10:10)

(ix) The Book of Revelation reveals a ‘king’ among them who will ‘torment’ men vehemently for ‘their sins’:

“They have a king over them, the angel of the abyss. His name in Hebrew is Abaddon, and in the Greek, he has the name Apollyon (that is, Destroyer).” (Revelation 9:11)

*Note that ‘Abaddon’ (Hebrew) = ‘Apollyon’ (Greek) = ‘Destroyer’ (English)

(x) But even the ‘realm of the dead’ (Sheol/Hades) and ‘Abaddon’ (the destroyer) is ‘naked’ before God (even ‘they’ can’t hide anything from ‘the Almighty’):

“Sheol is naked before God, and Abaddon has no covering.” (Job 26:6)

“Sheol and Abaddon are before the LORD: how much more then the hearts of the children of men!” (Proverbs 15:11)