Psa 88:11 Will Your lovingkindness be declared in the grave Or Your faithfulness in 'Abaddon,(the underworld)?
Rev 9:11 They have as king over them, the angel of the abyss (the bottomless pit); in Hebrew his name is 'Abaddon' (destruction), and in Greek he is called Apollyon (destroyer-king).
The king of an "army of locusts"
Also known in the Bible as Pestilence.
And such a thing brings Famine.