The question was asked, “What is Lucifer (Satan) fighting for?” The response is simple. He is fighting to gain the souls of humankind, as many as possible. Satan hates God our Father, but he hates us even more – he hates us with a vengeance we cannot even begin to conceive – because we have the capacity to become gods by grace, whereas Satan gave up everything he had when he rebelled against the Father out of pride.
Satan sees us as worse than dust, worse than nothing, less than worms. It is tremendously humiliating for him to see human beings – less than him by nature – come fully alive in and through God our Father and His grace. Thus Satan attempts everything he can to destroy us forever and in every conceivable way.