Oni

The Oni are largely inspired by the samurai clans of feudal japan, organizing themselves into large kinship groups with an emphasis on warrior culture for all genders, as well as honor, spiritualism and familial ties. Their warrior culture leads them to hire out as mercenaries - with most clans picking and choosing who they work with based on whether or not their goals and morals align.
In more than one clan, orcs have settled in among the Oni, bringing more of a mercantile aspect of culture into the clans. Oni culture places an emphasis on a sort of destiny determined by what kind of Oni a person is. This is less "destiny" in the traditional sense and more akin to the Tiefling first names.
Oni are the children of Giants and Demons, and still use the abyssal language in their ceremonies. As part of their heritage, the Oni inherited the knowledge of keeping and breeding Behir, the serpent-like creatures created by the giants to aid them against the Dragons.
All Oni gain a +2 to their constitution score, a relic of their giant lineage. They also get a +1 in any ability score of their choosing except constitutin.
Generally Aka (red) Oni are more down to earth and tend to take pleasure in the simpler joys of life and focus with singular intent on those things that bring them joy. This often leads them to excellence at their chosen path, and yet for others can lead to a sort of aimlessness, always seeking something new or out of reach. When Red Oni are reduced to 0 HP, they can, once per day, instead fall to 1 hp, their passion carrying them ever onward.
Ao (blue) Oni are generally more clever and cunning, and tend to have an aptitude for High Magic and the arcane. They tend to be curious, which is why many Blue Oni end up leaving home to explore the worlds on their own. For those who's curiosity is piqued at home, by science, the gods, or even their fellow people, this often results in a deep devotion to what they search for their knowledge in. Blue Oni have the innate ability to harness and release magical power. Once per day, they can cast Magic Missile without expending a spell slot. They also know the Dancing Lights Cantrip
Shiro Oni or Pale Oni are most often more closely connected to the worlds of spirits and gods. They are among the most rarely born of all, and often find themselves in positions of spiritual leadership. For those who tend more towards the warrior's path, this often leads them to follow their hearts on journeys of righteousness. Pale Oni can be stubborn when their heart calls out a path to them. Perhaps they simply see what others cannot. Shiro Oni know the Guidance cantrip and, once per day, can cast the spell Detect Evil and Good witnout using a spell slot.
Kuro Oni, or Dark Oni are the rarest of all to be born, though some Oni become Dark with age. Kuro Oni are said to be the most deeply connected to the Deep Magic of Aard and the primordial gods. Often aloof and pensive, they usually find that they have great skill in arts, which allow them to express the deep wells of emotion and power that they can feel all around them. Dark Oni are said to walk on the path of destiny. Once per day, a Dark Oni can cause any d20 to be re-rolled, but the second roll must stand regardless of what it is.
More rarely still is the event in which an Oni child is born who exhibits more than one coloration. These children are said to be those who's actions can change the fate of nations. It is most common among the Pale and Dark Oni, and more rarely among the Blue. Almost never is a child born with red coloration as well as another.

Naming Traditions

Unisex names

Oni names are largely based on Japanese, with names like Yamato and Megumi, but this is not a hard and fast rule.

Family names

Oni family names are usually their clan names, such as Silvermist and Stormtide. Most are compound words, but not all.

Other names

Oni who do great deeds may come to be known by a title, such as Manslayer, or Hitokiri, or Serpent Speaker.

Culture

Major language groups and dialects

Oni speak Giant most often, but Abyssal in religious rites, though often only the spiritual leaders of the clans speak it fluently. They also often speak Orcish and Gnomish, which are the languages of their most common neighbors in the Broken Bridge.

Shared customary codes and values

A strict code of honor permeates Oni culture, which extends to rules when they war amongst each other. In this way, the Oni are extremely divorced from their demonic heritage. Ideals of right and wrong can vary greatly among the Oni, but what is honorable and dishonorable is easily agreed upon.

Average technological level

Feudal Japan - but with Behir so, pretty cool.

Common Dress code

Oni tend to favour clothes that are easy to move in, as frequent attacks on their territories from pirates, other clans, and warring factions have taught them the importance of readiness. They also almost always have at least one weapon on them.

Art & Architecture

The Broken Bridge is based on Meiji Era japan, with the Oni representing the feudal samurai culture, producing many works of literature, beautiful silk work and paintings of rare beauty.

Coming of Age Rites

When an Oni is deemed of age, they receive their first real weapon. This is an important moment for a young Oni, and they are expected from then on to uphold the ideals of the clan as a fully fledged adult.

Funerary and Memorial customs

When Oni die, they have a number of diverse burial customs. Many release the bodies at sea, to return to Orochi, while the Raven Queen guides their souls beyond. Others perform sky burials atop mountains, to give the bodies to Adhar, still others cremate the bodies in volcanoes, dedicated them to the Bloodfire. They rarely bury their dead.

Common Taboos

Dishonor. To relinquish a weapon unduly, or to destroy it. Slavery is considered a taboo all over Aard, but especially among the Oni, who see it as a crime worthy only of the demons from which they parted ages past. It is a crime punishable by the ultimate fate; to have your weapon shattered, the pieces melted, and made into shackles, the body to be hanged and buried in stone so that the soul might never rest, nor the body return to any god. In the same fire that melts the weapon, a brand with the Abyssal symbol for "evil" is heated and branded onto the criminal - though this branding is not limited to capital crimes - it is part of the process of stripping one's clan name from them.

Historical figures

Sekirohiko of clan HeavenlySerpent, known as the Hurricane Sword Saint, who single developed a sword fighting technique for taking on multiple enemies and used it to defeat countless foes. He was a Pale Oni.

Sanosuke, of no clan. A red Oni, he was called the Crimson Saint, and was a barbarian of near unstoppable fury. Unlike other clanless Oni, his clan were unfairly exterminated by a warlord who used them as a scapegoat, so he wore the symbol for Evil on his clothes, and became a wanderer, later going on to save the citizens who lived under the rule of the warlord who killed his clan, before disappearing from history.

Ideals

Beauty Ideals

Oni prize their horns and the vibrant colours of their skin.

Courtship Ideals

Proper courtship amongst Oni tends to be formal, as there are many layers of social respect and honour that must be carefully navigated as two Oni get to know each other. This is especially true when they are two Oni from different clans, as the relationships between the clans must be navigated as well.

Relationship Ideals

Honour plays a large role in Oni relationships, and within a family and clan unit, each partner is expected to preserve and defend the other's honour.