In a society which values personal honour and achievement, swearing an oath is a serious undertaking. Oaths invoke the gods and have a magic of their own which applies to both mortals and immortals. Anyone deliberately breaking an oathbecomes a social pariah and angers the gods. Champions who break an oath are reviled for betraying everything a Greek, mortal or immortal, values. However, oaths bring power and those who uphold their oaths are loved by the gods and the people.
By swearing an oath a person declares they are dedicated to completing a task, with great cost to themselves if they fail. Each oath is sworn in the name of a god, either to complete the task in their name or to ask the god for their aid in the task. If the cause is worthy and the god is paying attention the mortal will be granted aid. In the game an oath becomes a status effect usable as an advantage or as a hazard against the character if they betray the oath.
See 'Love, Oaths & Missions' on page 92 of the 6d6 RPG Core for the rules on taking an oath (Hazards & Dangers). This section covers how oaths work in the Hellenic world.
Oaths consist of three parts: the name of a god, the price the oath-taker is willing to pay if they fail and the task to which the oath-taker is committing themselves. The gods whose name is invoked may be the champion's patron or the god within whose realm the task falls. A hero swearing to defend the borders of a city may call on <Apdx ref="open:settings:6d6hellenic:apdx:hecate">Hecate</apdx> while one swearing to slay their enemies may call on Ares. The more appropriate the god, the more likely the god is to take notice of the oath.
The swearing of an oath can take any form and be as public or private as the champion wishes. Oaths taken in an elaborate ceremony performed in a temple attended by priests are no different from oaths shouted across a noisy battlefield in the heat of the moment.
Oaths are sworn on something precious, such as the honour or life of the swearer. This is the ante or bet the oath-taker is staking and it will be forfeit if they fail. The oath-taker can put anything of value to themselves at stake in the oath but the higher its value the more likely the gods will listen. The consequences of failing the oath and losing their stake must be significant. This is not a game mechanic but something to be role played and the Game Leader must make the oath-taker's failure a real price to the character.
Oaths are magical and the oath-taker can swear on something they value but do not control. For example, swearing an oath on the honour of their home city. Even if the oath was secret, those affected will know through omens and portents of the champion's failure. The people of the city will turn their backs on the champion, banning them from the city on pain of death, and their name will become a curse word. As the city they love loses honour and prestige through disasters and defeats, the helpless champion can do nothing but watch. Oaths only have power because the personal consequences for the oath-taker are meaningful.
The task the oath-taker commits themselves to must be something important and on a grand scale. It must be above and beyond what is expected of an ordinary citizen. A caravan guard cannot swear to kill the bandit shooting at the traders, as that's already their job. However, if she loves the lead trader's son who has been taken as a slave, the guard can swear an oath to track down the bandits and free him.
To be meaningful the task must be possible but very difficult. Swearing to do something that is easy will be mocked by mortals and by the gods who will judge, and may punish, the swearer for taking oaths lightly. Impossible tasks such as exterminating the Persian Empire are similarly ridiculed.
Mortals who wish to please the gods must avoid hubris in their oaths and not attempt actions reserved for divine beings. Hubris is despised by all gods, so an oath to serve Ares by killing Athena will anger both of them - mortals cannot kill gods. Anyone taking such an oath will find the gods have very inventive ways of punishing hubris.
Once the sworn task is completed the character loses the status effect granted by swearing the oath. They gain the favour of whichever god was named in the oath and attract the favour of Hera, goddess of oath keepers. Oracles and portents will spread the news of the success quickly throughout Greece and the champion will win renown as a person of honour and skill whose word can be trusted. Stories will be told of their great deeds and even their enemies will respect them.
Failure to complete an oath brings shame, but this is mitigated if the champion made an honest attempt to fulfil it. Dying in a failed attempt is always considered an honourable act and will count favourably when the mortal is judged in the Underworld.
Regardless of how honest the character's efforts to fulfil the oath were, whatever was staked on the oath is forfeit. How this occurs is up to the Game Leader and the loss may not be immediate. A champion who swore on their life that barbarians will not breach the city gate might not die when the city is invaded. In Greek culture someone who has sworn on their life but didn't die is expected to take their own life. Alternatively, fate will find a fitting end for the champion in the near future.
The final consequence of failure is that the oath will be unfulfilled and count against the hero when they stand before the Judges of the Dead. It will hamper entry into the Isles of the Blessed, perhaps condemning the soul to Erebus. The success or failure of an oath will have repercussions after a hero's death.
To give up or renege on the terms of an oath invokes the wrath of mortals and gods alike. The god invoked in the oath will curse the mortal and other gods are likely to make the champion's life difficult. Hera the goddess of oath keepers will be most angered and will seek to make an example of the champion. Mortals everywhere will reject the oath-breaker and they will find every door and gate slammed in their faces. On their death, oath-breakers are destined for Tartarus.