The Akemenos-Ekemon Moieties

The population of the Eastern Settlements is mostly an even mixture of races. The Akemenos-Ekemon Moieties are the exception that makes the rule.
These are two enclaves of Tieflings, with strong internal cohesion and a strong alliance between them. The Akemenos community is located by a port town on the coast, midway along the Eastern Settlements. The Ekemon community is located inland at a central hub-city that puts them in a valuable position for trade.
The two communities have extensive contact - though they are far apart, there is much beneficial trade conducted between the two. The inland clan collect goods from other settlements and the coastal clan facilitate trade for these goods with other ports and nations. Additionally, the coming-of-age rites and marriage traditions provide strong ties between them.

Culture

Each of the two communities is centred on a Dojo and much of their culture revolves around adherence to that community's martial arts practise. The Akemendo form focuses on grappling and redirection of the opponents energy and movement. The Ekemondo form emphasises fast strikes, dodges and parries.

Coming of Age

By around age fifteen children are expected to have reached a particular level of capability within their moiety's martial art. Once they have reached this level of "presentability" they will be sent to live at the other moiety for a year. While there, they will receive training in that moiety's martial art form. At the end of the year they must demonstrate that they have gained a proficiency in this new form and have integrated the two forms.

Marriage

There is strong traditional expectation that members of the Akemenos community will marry members of the Ekemon community and vice versa. After marriage, the husband moves to the home community of the wife.
Marriage comes about sometimes for love, sometimes for status or connection. When a couple wish to be married, the husband-to-be will travel with one or more female family members to the home of the wife-to-be. There he will be met by her family.
On the First day they will conduct formalities (and these can be quite extensive) and rest from the journey.
On the second day, the husband-to-be will spar with male members of his wife-to-be's household. The intensity can vary considerably. If her father does not wish for the marriage to go ahead, the fight may continue until one man or the other is unconscious. If the father welcomes the marriage he will not go easy on the husband-to-be (that would be dishonourable), but he will concede the match once the man has shown that he is a capable protector.
On the third day the wife-to-be will spar with the women who came with the husband-to-be. Much like the second day's sparring, if the groom's family does not approve, the wife-to-be will have her work cut out for her. Even if they do approve, she will have to prove herself.

Origin

These communities formed in response to a lack of broader leadership and unity in the region - the Eastern Settlements have no overall ruler and no overall rules. The elders of the moieties settle disputes amongst members. If an outsider commits an offence against a member, they risk retaliation from the whole community. A history of violent retribution is a valuable asset in a region that sometimes suffers from lawlessness. The moieties consider that maintaining the perception of their strength and honour is vital to their continued survival and operation.