It has never been entirely clear whether Hellfire Jars are the product of an alchemical master, or whether they are in fact jars of true hellfire. In either case, the objects themselves are blessedly rare. And those who know of them consider them far too dangerous to use–unless they have the lack of good judgement and scruples normally associated with brigands and traveling adventurers.
When released from its ceramic jar, the fire will immediately fill a 10x10ft area, and expand at a rate of 1ft per minute. The hellfire burns sand, and stone, and steel just as a normal fire would burn wood. It reacts the water the same way normal fire reacts to lamp oil. Regardless of what is placed in its path, the hellfire will spread at 1ft per minute. Curiously, the hellfire does not consume anything on which it burns. If put out, it will appear as though the fire was never there.
The fire’s only weakness is the turning ability possessed by goodly clerics of level 3 or higher. A cleric of the appropriate level will instinctively feel the urge to turn the fire, upon seeing it. They need not make any check to perform this action, the fire will simply die down before the power of their faith. A single cleric may clear 10ft per level, per turn. (So, in 10 minutes, a level 3 cleric could clear 30ft of flames).
Any living creature caught within the hellfire’s area of effect is completely immobilized by pain. They will writhe and toss, but cannot coordinate their body sufficiently to run, or even move purposefully in any direction. Every turn which a person is subjected to this tournament will cost them 1 point of permanent wisdom loss. A reduction of 3 or more will leave a character with severe PTSD. In practice, they can never be within 15ft of any fire without entering a catatonic state for 1d6 turns. A wisdom reduction of 6 causes permanent insanity.