I was thinking about this quest while playing Battlestar Galactica earlier, and well, things just kind of took on a life of their own from there. So, here's a traitor variant I thought of for the By a Brother Betrayed quest:
First off, while I'm basing this off of the quest in the Compendium (and errata), the rules should work with any quest, there's nothing special about the layout (aside from needing a certain number of chests). Admittedly, I haven't tried out the original quest, though I already have some minor issues with the map (why is there a gold chest fairly close to the entrance, and why is it only guarded by non-master sorcerers and beastmen?), and I might recommend tightening it up a bit before playing. Regardless, aside from the map itself, the preparation works like in the scenario (with errata) aside from where described below.
Hints of Treachery
This scenario requires at least three heroes, and up to five. No player should have more than one hero under their control.
Before beginning the game, some preparation is needed. The overlord will need to prepare five cards to deal out to the players. Each card should have identical backs (or sleeves). On each card, the front should say "Traitor", "Aim", "Rest", "Guard", or "Dodge". If playing with four heroes, omit the Dodge card. If playing with only three heroes, omit the Guard card as well. Take one set of order tokens, shuffle them up, and place one face-down under each chest on the map that has an heirloom. Again, omit the Dodge order if playing with four, and both Dodge and Guard orders if playing with three. Hero players may not look at these tokens, but the Overlord may look at them at any time. He may not change which chest has what token, however.
After setup, shuffle the cards and deal one to each hero player. Players may only look at their own cards, except for the Overlord, who may look at any player's card (but may not change who has which card) at any time. The players with the Aim, Rest, Dodge, and Guard cards are all normal heroes. The player with the Traitor card is the traitor. The traitor does not win or lose with the heroes, instead he wins or loses with the Overlord.
A Hidden Traitor
The game plays like a normal game of Descent, except for where noted below. First, don't count the traitor player when selecting which monster statistics to use (so if there are four players, use the 3 player cards; if there are six players, use the 5 player cards). Also, the Overlord does not count the traitor when gaining threat from curses in chests or for the start of his turn.
During the game, all players are under suspicion by the other players, and for good reason - one of them wants to kill the rest! In order to solve who the traitor is, the players must find the heirlooms hidden inside treasure chests in the dungeon. Whenever a hero opens a chest with an order token under it, the order token is revealed. The player with the matching order on his card now reveals his card, showing that he is indeed on the side of the heroes.
Any of the heroes may declare that he knows who the traitor is, and accuse him by attacking the supposed traitor. If the attack is enough to kill the other player, the other player will reveal his card. If he is the Traitor, he immediately respawns in any square of his choice (only in a revealed area) and follows the instructions under "The Traitor Revealed", below. Otherwise, that hero is wrongfully accused. The heroes lose conquest tokens for the death as normal, but the hero does not appear in town or in the dungeon until the party manages to find the order token for his card. As soon as the party finds that order token, they realize their mistake and release their friend; he immediately appears in town as normal. Alternatively, if the traitor is revealed, all falsely accused heroes immediately appear in town.
At any time during his turn, the traitor may reveal himself by flipping his card face up. The heroes, taken by shock, immediately end their turn. Follow the directions under "The Traitor Revealed", below. The traitor may finish his turn, then the overlord takes his turn as normal.
Finally, even though the traitor can be killed by monsters as normal, he is not worth conquest tokens. Whenever a hero is killed, the party loses conquest tokens as normal, then the hero takes threat tokens equal to the conquest lost. When a hero is revealed to not be the traitor, he discards all of his threat tokens. As long as the traitor is not revealed, the party is allowed to go into negative conquest (the overlord gains conquest instead of the party losing conquest in this case, and loses conquest instead of the heroes gaining conquest if they are already negative). When the traitor is revealed for any reason, all his threat is discarded, then the party regains conquest tokens equal to the threat discarded.
The Traitor Revealed
As soon as the traitor is revealed for any reason, the Overlord's dark blessing energizes him. He immediately heals to full wounds, and gains five wounds per hero player. His armor also becomes five, unless he can raise it further without the overlord's blessing. Additionally, he discards any threat he may have accumulated and the party recovers conquest, as noted above. Finally, if any heroes were removed by false accusations, they are immediately returned to the game. From now on, the overlord can play cards on him as though he were a monster, although he may not play cards that trigger when a monster is activated, such as Rage or Charge.
The traitor will always take his turn after all hero players, but before the overlord. During his turn, he acts as though he were a hero player, and may take any hero actions he chooses, such as drinking potions, opening chests or doors (including doors to unrevealed areas), and picking up treasure. He may not activate glyphs or take a glyph of transport to town, however. If the traitor has a guard order, he can interrupt the hero's turn instead of the overlord's. Additionally, the hero players may interrupt the traitor's turn if they have a guard order.
If the traitor picks up a coin pile or opens a chest, only he gains any benefit from the loot. Any conquest tokens gained from the chest are lost, but the overlord still gains threat from curses. If the normal heroes open a chest or loot a coin pile, the traitor does not gain anything.
Ending the Threat
The heroes win if they manage to unmask and kill the revealed traitor (remember that he must be killed after revealing; if he is accused and killed, he is healed to full and revealed instead). The overlord and traitor win if the party is at 0 conquest after the traitor is revealed, or if the traitor is hidden and his threat from deaths is less than the heroes' negative conquest value, he may immediately reveal and force the heroes to lose.
Notes on Secrecy
As this scenario relies heavily on secrecy, certain things may not be done during the game. A player may not reveal his card, nor may he look at another player's card (except for the overlord, who may look at any player's card). The overlord may show any or all cards in his hand to a player, but that player may only pass the card back after looking at it, he may not disclose what the card was. Similarly, if playing with feat cards from Tomb of Ice, players may show each other or the Overlord their cards, but no player may disclose what he sees from another player.
E r i c k N. B o u c h a r d
Nice to see scenario ideas for Descent! I hope to see more in the future!