Two ancient city-states had grown to become rivals in all things: art, architecture, music, mathematics, engineering, commerce, and martial prowess. This rivalry came to a head and war broke out. As the two city-states were equally matched the war raged on for many years with great destruction to the land and heavy losses on both sides.
Finally accepting that this war had cost both city-states dearly, the leaders of both agreed that the war should be decided in one final contest: a dozen of the best warriors from each city-state would meet at a designated place and fight to the death. There would be no magic and no ranged or distance weapons – no javelins or spears, no bows and arrows, no slings and stones. Each combatant would be armored as usual with breastplate, helmet, greaves, bracers, and shield and armed with only a short sword. As much of the land had been decimated after years of constant war it was difficult to find a suitable field for battle, but after some time a small olive grove on a somewhat secluded hillside that had mostly been spared by the war was chosen.
At midday of the summer solstice the twenty-four warriors met in the olive grove and a quick and brutal battle ensued. The fighting was over in mere minutes, ending with the last two warriors, one from each side, plunging their swords into their opponent’s torso, each dying in the other’s unyielding grip. Thus, the needless and pointless war ended in a draw, the citizens of both city-states returning to their former lives to pick up the pieces as best they could.
This war and specifically this battle had not gone unnoticed by the gods of War. They thought that the final resting place of these twenty-four valiant and tenacious warriors should not be in the cool ground of some quiet, lonely olive grove. Nor did they think that it was fitting that great warriors should rest at all, especially when they were denied the satisfaction of a clear victory. To this end, the gods of War looked throughout the Divine Plane for some place that seemed fitting for these warriors to continue on with their battle, but no place could be found. So, the gods of War traveled to the Demi Plane and there, after much searching, found a suitable place for the Olive Grove and warriors to reside. And there the warriors continue their contest from the first ray of sunrise to the last ray of sunset. Many times dying and coming back to life to fight that battle anew. In keeping with the setting of the original battle everyday is the summer solstice. At the end of each day the fighting halts at sunset with the warriors being frozen in a state of suspended animation in whatever position they may be in, becoming reanimated at sunrise.
Maybe unintentionally the gods of War created a trap for mortals and even some immortals. If any sentient being sets foot in the Olive Grove from sunrise to sunset that being is automatically assigned to one of the sides and becomes part of the battle; their clothes and armor either taking on a light sky blue color or dark emerald green. If that individual should survive until sunset they are allowed to leave the Olive Grove, if they are so able. However, if they take anything from the Grove that does not belong to them they will be frozen in suspended animation just as they are about to leave and are once again a combatant. If they eat of the olive trees, drink of the water, kill and eat any of the small game or animals from the Grove that will also result in the individual being frozen in suspended animation and again becoming a combatant. If an individual does not survive to sunset than they become a permanent combatant of the Olive Grove – unless someone or thing can physically, non-magically, take them out of the Olive Grove during the night. Should anyone try to take a combatant from the Olive Grove during the night and do so with malicious intent, that individual is frozen in a state of suspended animation and becomes a combatant for the next day. Individuals wishing to pass thru the Olive Grove or take refuge in it safely may do so only at night and only if they do not take or consume anything from the grove. While in their state of suspended animation the combatants cannot be harmed. The original twenty-four warriors can never be removed from the Olive Grove.
With all these conditions the gods of War set upon the Olive Grove, few mortals end up leaving and over the centuries the battle has grown from the original twenty-four combatants to thousands, the Olive Grove itself growing from just under an acre to now over one hundred and twenty acres. You will find warriors from seemingly every race, time period, and culture of the world represented in the olive grove – still fighting in close quarters combat – as magic and ranged/distance weapons are not allowed in keeping with the original battle. You will also find wizards, thieves, scavengers, and average folk who all unwittingly became prisoners of the Olive Grove. Those individuals who are permanently trapped in the Grove retain all their knowledge, skills, traits, and personality with the addition that they want to fight and destroy those combatants wearing a different color than they. When first being trapped in the Olive Grove individuals do not have this wish to fight those not wearing the same color as they. This wish to fight members of the opposing force only takes hold if the person is slain during combat and rises again at the start of the next round of fighting. The battle continues until all the members of at least one side have been killed. After which, all slain combatants rise to life, fully healed, with all their gear restored to their state before combat. Any magical items brought into the Grove cease to function magically. Any ranged weapons or weapons that allow an individual to keep an enemy at a distance are turned into the short swords used by the original twenty-four warriors. (At DM’s discretion – this transformation may only take place during the daylight hours).
Ideas for gameplay:
A rescue/retrieval mission.
A wizard or other individual some years ago was lost and has recently been seen (or it has some other way been uncovered) engaged in battle in the Olive Grove, or the players have been hired to investigate the disappearance of some individual (gone for years or just recently). Or, there is some task or bit of information the missing individual has that is crucial for some larger task the players have and this puts them on the search. The players must find some way to the Demi Plane (or other place the Olive Grove could be) and once there survive as they navigate thru the Demi Plane to the Olive Grove, not breaking the rules of the Olive Grove, retrieve the lost individual, and then trek back thru the Demi Plane and then back to the Mortal Plane.
The Olive Grove could be in your world or any plane you may choose to put it.
To increase the difficulty, there could be others after this lost individual and those others may try to stop the players from getting to the Olive Grove and/or try to steal the missing individual away after the players save said individual from the Olive Grove, or outright try to kill the individual.
The individual in question might also be needed to be retrieved to stand trial for past wrongs of some kind.
Accident.
The players were traveling thru the area where the Olive Grove is and accidentally set foot in it, more than likely at night. Or, the players were being chased by a more powerful force or opponent and sought refuge in the Olive Grove, or tried to cut thru.
The players decided to stay the night in a quiet part of the Olive Grove where they did not happen upon any combatants and the players either ate or drank of something native to the Olive Grove, or stayed camped in the Olive Grove until after dawn and became combatants, automatically assigned to one side, or some to one side and some to the other, and now must survive until sunset or become permanent members of the Olive Grove.
Tricked.
The players were told that powerful weapons and armor could be found in the Olive Grove, end up being permanent combatants, until the one that tricked them (thru intermediaries or disguise) rescues them (or just one of the players), to blackmail the players for the deceiver’s own end. “I’ll help you get your friends out if you do a little task for me.” Or, “I got you out, you owe me.” Or, “It was no trouble at all to assist you, now perhaps you could assist me.”
If all the players get permanently trapped perhaps some individual or individuals come along and rescues one or all – for a favor, and this sets the players upon some quest they are now honor bound to carry out. Or are they? What will happen to the players that were rescued that don’t return the favor? Perhaps the individual that rescued the players needs the players to get the individual out of the Demi Plane, or wherever they happen to be.
Sending characters to the Grove may be an ideal way to challenge high-level parties as magic cannot be used in the Olive Grove.