As a horror writer, finding new words that relate to total destruction are so fun like, yeah! Can’t wait to throw this in somewhere!
INTERNECINE, adj. of, relating to, or involving conflict within a group; marked by slaughter, deadly, especially mutually destructive
Internecine comes from the Latin internecinus (“fought to the death” or “destructive”, which traces to the verb “necare” (“to kill”) and the prefix inter-. Inter- usually means “between” or “mutual” in Latin, but can also indicate the completion of an action. Internecine meant “deadly” when it first appeared in English in the early 17th century. When Samuel Johnson entered it in his dictionary almost a centuary later, he was misled by “inter-“ and defined the word as “endeavoring mutual destruction”. Johnson’s definition was carried into later dictionaries, and before long his sense was the dominant meaning of the word.