Flambeau?
I’m still not quite clear if you’re looking for a noun or an adjective, or if you want to focus on its agency or on the results.
Fireball? All-consuming fire? Fire-consumed? Smouldering embers?
Inflamed, hot as a pistol, hot tamale, hot pepper, spicy, solar, red hot Mama.?
Eta. Not sure what this is but, firebrand.
Consumed maybe?
Incendiary?
If it’s insured, the word is “money”.
If something is completely consumed by fire all that remains is carbon dioxide and water.
Some of the terms for the other products of fire include ash, brand, char, cinder, clinker, coke, ember, scorch, soot. . .
for a more dramitic effect there’s Pyrolysis
so maybe pyrolytic detritus . . .
mc
Debris is a term for anything that has been broken down or destroyed, though not necessarily by fire.
Cremated, incinerated.
Use some take on the “scourge” or “cleansing fire” from the Prophets (or is it Revelation?) Hell, bring in Moses and the bush, but you’re getting seriously complicated metaphors here…
Hot mess?
Thank you. I revised the paragraph so I don’t need that word any more, but if I need more fire words I’ll come back here.
(Though I could use a single-word noun that means “cruel person” or “spiteful person”. Do any exist?)
malicious and malevolent come to mind. . .so does thesaurus. . .
mc
sorry those are adjectives. . .
how about ogre or sadist or blackguard
Does this qualify as punting the question?
(LAMBEAU!)
Ha. That’s funny. That word actually means a kind of torch. I wouldn’t want to punt that.
Sauron was definitely a meanie. 
I was once a “Receiver of Wrecks” and was required to understand the difference between those terms 