1. The Background
The world was created from the Four Elements (Fish, Blood, Ashes, Bones) by the Old Gods, of which there were also four, though their names have been forgotten. When the world was in its infancy all was subject to the laws of Nature, and the elements reigned supreme.
Things carried on this way for a very long time, until eventually Men (featherless bipeds with the capacity to create art) were born. Legends and histories contradict each other on the nature of the first Man:
1. The first Man was a Giant, the ancient dead species of tyrants that built the ruins that dot the Old World and from which Ogres and Whales are descended. Giants created fire but were scared of it and made little use of it; the civilized races evolved later and developed Fire from the knowledge of the Giants.
2. The first Man was a Blin, a more-intelligent relative of the Ape from which the Goblin, Hobgoblin, and Bugbear (a corruption of “büg” from “big”, and “blyere” from “blyin” which means “man” in the Old Tongue, hence “goblin”, “hobgoblin” etc) races are descended. Blins created Fire in the rites of the primitive Sun-Cults that would eventually birth the Church; the other civilized races evolved later.
3. The first Man was an Orc (which race was the first depends, usually, on the orc reciting the myth), created or born somehow from the Old Gods before their death, and from which the other two races of Orc are descended. Orcs created Fire as a tool; the other civilized races were born from confluences of the Four Elements soon after.
4. The first Man was a Dragon, hatched from the egg of the World, and from which Kobolds (and hence, Dragons) are descended. Dragons were born with Fire inside them; the other civilized races were created by Dragons.
5. The first Man was a Lizard, hatched from the egg of the World, and from which Lizardfolk are descended. Lizardfolk created Fire to warm themselves; the other civilized races came about by means unknown, except the first Dragons which were a divine punishment upon the most cruel and greedy Lizardfolk.
6. The first Man was a Dog, sculpted from mud by the Old Gods, and from which Gnolls (and of course Dogmen) are descended. Fire was given to the Gnolls and Dogmen in secret by the Old Gods; the other civilized races were created later to provide competition and test their skills.
7. The first Man was a Minotaur, brought into being through the force of his own will, and from which all other civilized races are descended. Minotaurs were granted mastery over Fire by God, and shared with with the other races.
8. The first Man was an Elf, a dead race something like an Orc without tusks or a Hobgoblin without fur, and from which Moth Elves were created through a powerful curse for reasons lost to time. The other civilized races were created by the Old Gods to punish them, and Fire came with them.
Regardless of legend, all tell that Fire is the Fifth Element, the False Element, and the greatest symbol of Man's triumph over Nature. Because of this, Fire has been in continual conflict with the Four Elements ever since.
There are four types of fire.
Also called ashfire, hellfire, unholy fire, witchfire, dragonfire, et cetera. If a type of fire is not specified, it's safe to assume it is natural fire. Even fires kindled by other types are typically natural. Natural fire creates smoke, leaves ash, and is an aspect of Ashes rather than Fire itself.
Also called sunfire or consecrated fire, it can be created by paladins, truly devout priests, and angelic beings (including Fire elementals). Holy fire is Fire made manifest, burns clean and bright with little to no smoke or ash, cannot harm the truly faithful, and deals double damage to unholy undead, demons, natural elementals, and other aspects of Evil or Nature (which are the same thing).
Faerie fire appears in every way like flame but scintillates through hues from indigo through candy-pink, and burns without heat. It can only be created by fey magic. It cannot kindle other fires, and only burns what the fey that created it wishes to.
BATTLEFIRE is the rarest and most dangerous type of fire, and can be created only by BATTLEMAGES or mundane warriors who have achieved complete mastery of their martial techniques. It is a coruscating rainbow of color, shot through with octarine spectres of death and violence, and carries with it the sound of battle-cries and clashing steel. BATTLEFIRE always counts as the most damaging elemental type against any target. For example against unholy undead it counts as holy fire, against a stone wall it counts as acid, &c &c.