Are Idols non-entities or faces of demonic powers

It is interesting how in 1 Cor 8:4, Paul can say that idols “nothing,” but then in 1 Cor 10:19-21 he associates them with the worship of demons. Are idols nothing or are they a front for demonic powers? Perhaps it is the case that: “Idols are nonentities, but demonic powers used idols to inveigle humans into worshipping false gods” (David Garland, 1 Corinthians 372).