Nocturnal Humans

The people call themselves "humans" and "humanity." I added "nocturnal" to the name just to differentiate them from the sub-species Auroral Humans (the "creatures" that the seed refers to) and from real-life humans. They aren't a populous race, and they stick to their familiar peninsula.

Basic Information

Anatomy

Nocturnal humans look much like real-life humans do, with pale skin to better blend into the snowy environment. They do have a thicker layer of fat beneath the skin for a bit of natural insulation.

Additional Information

Perception and Sensory Capabilities

The biggest difference between Nocturnal Humans and real-life humans is that the ones in Umbral are naturally nocturnal. They can see as sharply by the light of the full moon as real-life humans can in full daylight.
Every member of this species has achromatopsia, aka total color blindness. They only see in shades of black and white. Other symptoms are the inability to see in bright light and an instinctual fear/avoidance of bright light. Twilight is the upper limit of what they can stand without protective glasses.
The cause is purely genetic. The cones (organs in the eye that enable color vision) are intact but non-functional. In this species, color vision is tied to a recessive gene. This becomes relevant to Auroral Humans and the auroral fever.

Civilization and Culture

Naming Traditions

Umbralans use the first name last name convention most readers are familiar with. What's different is that the parents choose both the first and last name for their child; there's no universal force of tradition pressuring the parents to give the child one family name over another. Many families alternate between both parents' surnames based on birth order or the child's gender. Meeting full biological siblings who have different last names is very common. Other families use hyphenated last names. Some families get creative and create new surnames by fusing elements of the parents' surnames.
When children become legal adults (16 at the time of this story), they have the opportunity to legally change their name, including their last name. Every teen fantasizes about changing their name, but the steep fees (and layers of bureaucratic red tape) attached to the process weed out most of the ones who would do it insincerely. More often than not, the person wants to rid themselves of an unfortunate name (Butz, Fanny, and the like) or honor a beloved parent or family member. Orphans who want to share the name of their adoptive family or honor the people who raised them are another common scenario.

Relationship Ideals

Marriage is not a legal institution in this society. It is only a religious ceremony and blessing upon the couple and their offspring. The only real benefits it confers is social points with religious folk and opportunities for mobility into elite circles. Only children of married couples can become clergy, and the clergy favor children of married couples for the position of prime minister. Marriage is strictly for heterosexual couples.
Most middle class, lower class, and academic class couples choose not to formally marry. Common law marriages are the norm in Umbral. Homosexual couples are rarer but don't face much prejudice from ordinary folks. They're regarded as legitimate as heterosexual couples in a common law marriage, and they can freely adopt children.
Married or not, long-term couples are expected to live together, especially if they have children. Faithfulness to a single partner is a virtue.

Common Etiquette Rules

Polite Address: For adults, this is "Good." It's the equivalent of Mr./Ms./etc. For children, it is "Young" and works the same way. One step down would be addressing someone only by their last name. While a faux pas in ordinary circumstances, this is common in government and legal proceedings, since the title "Good" could sway those present to feel undue sympathy toward the accused and other suspicious people. Journalism and historical writings about these proceedings usually follow the same practice.

Common Taboos

Having multiple sexual partners is not technically illegal, but is a big stain on one's reputation.