the.com/fire starter

means A person or thing that deliberately ignites conflict, chaos, or action — originally literal kindling, now mostly used for people who stir trouble on purpose.

from Straightforward compound of 'fire' and 'starter' — functional, literal English for the stuff (or person, by extension) that gets a flame going. The figurative sense, for someone who sparks drama, controversy, or unrest, rode in on the back of 'spark' and 'kindle' as fire-metaphors for conflict, which English has leaned on for centuries. No hidden backstory here — the word means almost exactly what it says, which is part of its dark comedy when applied to people.