Samuel R. Delany 
Towers of Toron [EPUB ebook] 

"We have received warning. The Lord of the Flames is loose on Earth once more." Once before the Lord of the Flames had been driven halfway across the universe. His return would mean a new era of chaos and conflict for the populace of Earth. The Lord of the Flames was a strange adversary – a force of evil devoid of physical substance. He sought warmth in unpredictable places: creeping into the soul of a worm or the stem of a flower or the mind of a man.