“Burning oil will deter many monsters from continuing pursuit.”
—Gygax & Arneson, “Dungeons & Dragons Volume III: The Underworld & Wilderness Adventures”
Burning oil is the traditional equalizer for low-level parties in old school D&D. It’s a deadly ranged weapon that’s also dirt cheap and usable by anyone. Despite the risks of setting oneself on fire, it’s the most effective tool that starting PCs have for dealing with their enemies, dealing an average of 9 damage over two rounds—enough to kill even the toughest normal man or orcish sergeant.
But… why is it so deadly?
Clearly, dousing someone in burning oil is going to be deadly. In fact, in the Chainmail ruleset, dumping a cauldron of burning oil on targets kills them instantly! But using this as a baseline for the effect goes against the core of D&D combat. It’s like saying that running someone through with a sword will be deadly; this is true, but it’s also not a presumed effect of any successful attack. And just as a successful melee attack might reduce the target’s hit point total through a bruise, a graze or even a threatening near-miss, a successful burning oil attack might drench an easily-removed cloak, deliver only a few burning droplets or even result in a threatening near-miss.
On the other hand, burning oil isn’t actually that bad in terms of game balance, since it takes two rounds and two attack rolls to set someone alight—one to douse them in oil and another to hit them with a torch. This doubles the combat effectiveness of the party’s dagger-wielding magic-users, but isn’t nearly as beneficial for more fighting-oriented types. Alternatively, you can spread the oil on the floor in advance and light it when they come into range, but most opponents will be able to withdraw from the burning area after one round, and you risk getting pushed into your own oil patch or having it block your own escape.
Things really break down when you allow players to make and use oil-based Molotov cocktails. These are allowed in the Rules Cyclopedia, but there’s no mention of them in pure Red Box. Pre-lit oil lets you deal 2-16 damage with one attack roll. That’s definitely unbalanced at low levels, and makes Molotov-lobbing first level hirelings effective even in the deeper levels of the dungeon.
- Allow a character hit by burning oil to spend a round rolling around and putting out the flames, thereby preventing the second round of damage from the oil.
- Disallow the use of Molotov cocktails, or make them sufficiently flawed that it’s a meaningful tactical choice as to whether or not to use them.
- Incorporate oil into the extant class-based weapon restrictions; it can be used by classes that can use any weapon, and as it lacks an edge it can be used by clerics, but magic-users can only wield daggers and thus cannot effectively throw oil (or at least suffer a penalty to do so).
- Consult Philotomy’s advice on burning oil for detailed suggestions regarding complexities arising from burning oil use.
- Set the PCs on fire and watch their oil flasks explode! (You may wish to employ a pyrologist for this purpose.)
This should make burning oil less of a trump card while still retaining its usefulness. It’s a decently effective weapon, a method to slay enemies resistant to ordinary weapons (such as mummies), a means to destroy wooden structures, and a barrier against hostile foes. There’s no reason for it to be anything more.