One who or that which causes devastation; an agent of destruction.
From devastate + -or (Latin agent noun suffix meaning 'one who'). This follows the standard pattern of creating agent nouns in English from Latin-origin verbs.
This word is rare because English prefers active descriptions ('it devastates') over agent nouns—yet it's been used historically for particularly destructive forces, like 'the devastators of Gaul' in Roman chronicles!
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