Merfolk live in pods ruled over by one of the many oceanic queendoms, all occupying the equatorial zone of the ocean. The queendoms are as follows, from west to east: The River's End, along the equatorial western coast of Kessix, where the An'ritil river meets the sea; The Sea of Shaking Waters, near Cinder Isle and along the eastern coast of Kessix; North of the Desert; along the northern coast of Tekeburi; The Coast of Many Ships, on the eastern side of the Three Point Sea near Aberia; and The Sea that was Split, on the southern Isahai coast around the islands of Zersei.
Unlike other seafolk, they are sedentary and build sea-fortresses along the coasts they live on. They live in villages of 100-150 merfolk, though within the village they cluster into pods of 15-20. Villages are led by a matriarch, who visits the central village in their region once a year to report to the queen. Despite the names, the queens can be of any gender, and since merfolk have loose attitudes toward gender in the first place, the same queen may behave as multiple genders throughout their reign.
Merfolk are hypersocial by nature, with a mind built for mapping huge webs of relationships. Everyone in a given village is expected to know each other and regularly interact, and those that have a hard time socially are seen as odd and withdrawn, even if they have a small group of friends. This hypersocial nature extends into romantic relationships as well. Most merfolk are polyamorous and never choose a single life partner, though three or four may live together if they were all to move out. Housing is arranged by generation, and all merfolk of a certain generation live together. To prevent accidental incest, merfolk are expected to remember family trees of both their parents, and one of the first matters discussed in a relationship is lineage. Some merfolk choose to get their family's name signs tattooed on their arm in intricate spirals as a mnemonic device.
Children are raised by all members of the village until they reach age 16, when they begin living in their generation's section of the village. During this first few years of the generation's gathering, there are many petty fights to determine the pecking order, and a smaller group tends to come out on top, eventually becoming the leaders of the smaller village groups.
Names are given when a merfolk child is five, and usually given by the mother. They have to do with a merfolk's visual appearance, so a bright-eyed merfolk may be called Star-Eye, while a magefolk born with a crooked tail may be called "Twisted-Tail". Names rarely change throughout a merfolk's life.
Merfolk have six different gender identities within their society: two that match each of their biological sexes, and four that are neutral/other. They are as follows: Tem, a "female" gender that is described as abundant and protective; Vai, a "male" gender that is described as bright and valiant; Ivet, when one feels both Tem and Vai; Aur, a gender that is likened to the deep sea and strength; Sela, a gender associated with the moon and spirituality; and Lait; a catch-all "none of the above". All children are considered Lait until they reach 16. Aur merfolk are more often at the top of their pecking order, and Sela merfolk are the most likely to become distant and outcast. In visual differentiation, the Vai are often the brightest and most decorated, while Aur merfolk prefer tattooing as a form of expression.
Merfolk are thought of by other cultures as vain and pretentious, since they as sedentary people are able to keep larger amounts of decorated objects, and much of their visual style is in regard to the upkeep of their hair, rivaling that of Iksandi nobles. They keep their hair long but tied back in rows of braids, and decorate it with shells and traded beads. These braids are usually done out of the water, as it makes the hair easier to maintain. Most merfolk villages hold hair-braiding ceremonies at specific phases of the moon, leading to various legends about merfolk seen brushing their hair by the light of the moon. Outcast merfolk will tend to braid their hair around the same time as their village, no matter where they are.
Merfolk villages are built around the coasts they live in. Some are built within existing caves, while most are tents made of woven kelp or interlocking domes of dead coral. In some areas, merfolk grow coral into elaborate structural formations around an existing frame, coaxing them into unique organic shapes.
In some areas, particularly in the Sea of Many Ships, architecture is mingled with the cultures they interact with. Coastal merfolk near Kanburi work with the Vishi to build arching, multi-layer structures that blend both land and seafolk needs.
Merfolk are fond of collecting things and trading with each other to get what they want. Seashells are a common de facto currency among merfolk, and shells from other parts of the world are worth more than shells from a given merfolk's home region. Pods meet often to trade information and items.
Merfolk play many games in small and large groups, usually based around agility challenges like obstacle courses and chasing games. Imaginative play is popular among younger magefolk, and common until around age 16. Since merfolk are non-nomadic, there are a wider variety of roles an adult merfolk can take, from fisher and farmer to hairstylist and weaver.
Trade with land cultures is common, especially in the Sea of Shaking Waters with the people of Cinder Isle. They trade stone tools for shells and underwater rocks, and often assist with fishing by driving prey into waiting nets.
Scouts play an interesting role in merfolk culture, as they are not outcasts, but spend too much time in small groups to be considered part of a well-balanced village pod. They spend most of their time on the edges of the kingdom, particularly north and south, to defend against sirens. Scouts keep their hair short, and are often Tem, Lait, or Aur merfolk. They are welcomed into whatever village they come across, since they are not seen often and come bearing news and stories.
Time is tracked by the phases of the moon, and on a smaller level, the tidal cycle, especially in extremely coastal areas.