So I've had a silly little idea for a while, and now that I've figured out how to do it I started writing up the stats for it. The idea behind it is a grapple-focused monk that starts every day by setting himself on fire, and then giving very warm hugs to the bad guys.
Catching on fire deals 1d6 fire damage per round, so I need to choose a race with resist fire 5 (Tiefling, Ifrit, etc) and take a Magic Basic Trait called Unscathed, which increases all of your resistances by 2. I now have resist fire 7 and I am immune to 1d6 fire.
Now I have 2 questions.
1) Catching on fire rules never actually discuss how to weaponize being on fire. My first reaction is that I am considered a bonfire (medium sized) so when I grapple enemies they are exposed to it and must make the standard DC 15 Reflex save to avoid catching on fire, not forgetting the grappling condition's dex penalty.
2) Equipment. The character is a monk, so he won't need a whole lot, but I was wondering if there were specific rules for equipment being flammable or not. Can I just say my amulet of mighty fists is made of steel? Do magic items with fire effects (things of shirts of immolation) count as fireproof? How much does an asbestos explorer's outfit cost? Technically the rules specify "Those whose clothes or equipment catch fire" and not "those who catch fire," so RAW can I light my hair on fire and not need to worry about equipment at all?
Spoiler:
Catching on Fire
Characters exposed to burning oil, bonfires, and non-instantaneous magic fires might find their clothes, hair, or equipment on fire. Spells with an instantaneous duration don't normally set a character on fire, since the heat and flame from these come and go in a flash.
Characters at risk of catching fire are allowed a DC 15 Reflex save to avoid this fate. If a character's clothes or hair catch fire, he takes 1d6 points of damage immediately. In each subsequent round, the burning character must make another Reflex saving throw. Failure means he takes another 1d6 points of damage that round. Success means that the fire has gone out—that is, once he succeeds on his saving throw, he's no longer on fire.
A character on fire may automatically extinguish the flames by jumping into enough water to douse himself. If no body of water is at hand, rolling on the ground or smothering the fire with cloaks or the like permits the character another save with a +4 bonus.
Those whose clothes or equipment catch fire must make DC 15 Reflex saves for each item. Flammable items that fail take the same amount of damage as the character.
Well, it's going to be your clothing and/or hair that burns. Once they burn down to nothing, the fire would go out. What you'd need to do is coat yourself in some flammable substance like oil or maybe have a spellcaster cast grease on you.
You are pretty far outside anything officially delimited in the rules, so you aren't going to get a real strong rules answer. I'll give you how I would personally rule on this, and why.
Unless your entire body was rapidly burning (which it won't if you are immune to fire) you are in no way a bonfire. Just your hair burning would probably be considerably less fire than a torch.
Hitting someone with a torch does one point of fire damage (plus improvised weapon damage) and that is about the most bonus I would give you for being on fire yourself. I would however allow you to come up with some sort of gloves you could dip in lamp oil and light for a fairly good duration, about as long as a torch and costing a similar amount (and that would avoid worry about destroying your own equipment).
Probably that isn't really what you want, and wouldn't fit the concept you have for this character, but that is about the furthest I could see bending the rules for this.
Burn seems a little too much in my opinion, especially the scaling reflex DC as opposed to the flat DC 15. One point (as a torch) seems a bit on the other side of the spectrum but I would take it, especially considering that I'm getting free damage out of a defensive ability.
The gloves are actually a pretty interesting idea, most evil minions would probably see them as magical fire gloves rather than mundane fire which might make my resistance slightly less obvious.
I also seem to recall some kind of magic tankard that would fill itself with alcohol whenever you willed it to, that could be a method of fueling.
