The fey elf setting draws from several inspirations. It continues a 4e setting. An important theme from the 4e setting is, the fey cultures are strictly magical. The feywild emphasizes magical power sources, namely psionic, primal, arcane, and divine. The fey divine is nontheistic but is heavy in healing, positivity, divination, fate, and luck. Only the material plane ("mortal", "natural") exhibits the martial power source. In this setting, any fey creature who has levels in a martial class, like Fighter or Rogue, has a backstory where they somehow learned these capabilities from the material plane.
Note, the sun elf and moon elf are fey, thus distinct from high elf and wood elf that are material.
The sun elf is Norsesque. The moon elf is Celtesque.
This post describes the Norsesque sun elf.
The sun elf comprises several cultures, because each governmental "court" has its own local culture. Even so, it is possible to talk about a composite culture, where most sun elf cultures share most of its features.
The real-life Viking-Period Norse culture is traditionally (ancestrally) a democratic local government. The local parliament is called a "Thing" (Þing), every adult − woman and man − votes as a member of this parliament. They vote for two community leaders, one "Jarl" and one "Law-sayer". The job of the Lawsayer is something like a supreme court, to remind everyone what the laws are. The job of the Jarl is like a US president, in charge of the day-to-day executive decisions, but most importantly, is the commander-in-chief in charge of the army. The government is much like the US government, where the Jarl is the president, the Lawsayer is the judicial, and every local citizen is congress. But the government is local, so the Jarl is more like a "mayor" in scope − but with a local army. The Jarl is typically a man because of the military duty, but there are women who are elected to be the Jarl. Essentially, the local Thing is within walking-distance of every voter.
The political description is somewhat complex. Toward the end of the Viking Period, there are a few regional Things, whose voters are representatives from various local Things. Moreover, by the centuries after the Viking Period, the Norse cultures shift into monarchies, but even then, the monarch is more like requiring an elected Jarl to come from a certain family. It is possible, to vote out an unpopular monarch, and vote in a sibling or cousin instead. During the Viking Period, there are aspiring monarchs, but their influence is more like a patchwork of alliances, making different arrangements with different regional and local Things. In any case, it is fair to characterize the traditional Thing as a local direct democracy, enjoying the participation of each nearby citizen. Politics tends to revolve around prominent families, and there can be intrigue and family feuds.
In the D&D setting, the politics of each sun elf "fey court" is like a local Thing. Every elf that is 100 years or older gets to vote on any issue. The voters typically vote as a block as a family. If a family gets annoyed with a particular court, they can leave that court and instead become members of a different court.
In the Norse culture, each family has its own militia. Typically, the culture expects the adult males of each family to fight as warriors to defend the family. (Family feuds are a thing!) Young girls and boys learn warfare together, such as wrestling and handling weapons. Adult females that prove capable in war can be members of a family militia. Even so, Norse masculine values come with a kind of military machismo. Men are expected to fight, and fighting is a mans world. Women who are good at fighting become members of a masculine gender-division of labor. The culture respects these female warriors for their masculine skills. Meanwhile, men who are less good at fighting might endure insults as a "coward" (ergi) or weakling, because of shirking the duty of a male to defend ones family. Nevertheless the culture still respects any men who excel at feminine skills, such as Norse shamanism. A Norse individual can choose ones own gender. The community will respect their respective accomplishments.
The job of a Jarl is delicate, because each family has its own warriors. No family trusts the safety of ones own family members to some other family. The Jarl must be an individual that each family trusts to keep the warriors of ones family safe. The need for every family to entrust this individual with their own warriors, is mainly why the democracy exists in the first place. Each voter needs to express confidence in this individual. In this way, the Jarl becomes responsible for heading the collective shared "army" of many families.
In the D&D setting, there is no "martial power source" from the feywild. By analogy, the fey elf "warriors" are strictly mages. Each family has powerful mages who defend the family. The sun court "songster" (a spell singer) is a Jarl, an elected official who each family requires to keep the mages of ones own family safe. The court is in charge of an army mages from many families: Psions, Bards, Clerics, also Druids, Wizards, Warlocks, Sorcerers, and any other fullcasters. An army of Wizards is a terrifying power. And so on. In times of emergency, many fey courts join their armies together in common cause. Other races tend to avoid provoking the fey elves. Magic is the currency of "hard power" among the fey courts. Art is the "soft power".
In the real life Norse history, there is a kind of machismo. Courage is the ultimate masculine value. To be a warrior who fights "fair", hand to hand, face to face, is an expression of such courage. This machismo makes the feminine magic, called Seidhr (Seiðr), problematic for men. Seidhr is mind-magic, literally a magic that "plays with an others mind", causing delusions and illusions, even possessions. In D&D terms, the schools of enchantment and illusion approximate well enough the Norse Seidhr. Essentially, the mage projects ones own mind into someone elses mind to wreak havoc there. The machismo considers it "cowardly" to use this magic to assassinate an enemy from a distance, or to cause an enemy to be unable to defend oneself, or to cause an enemy to kill oneself or ally. The removal of courage is itself unmanly. This military machismo is a main reason why "men" dont do shamanism. Of course, "women" have no obligation to conform to this machismo − and have no problem magically assassinating from a distance. Norse men fear magical women, and likewise respect any men who know how to do these kinds of magic.
The Norse culture gender divides, but there is real fluidity for individuals to choose to be successful in the skills of the other gender.
Among the Norse, the magic gender-divides. The men do warrior magic, called Ljodh (ljóð), "songs". The machismo considers this kind of magic permissible, because it allows a warrior to continue fighting face-to-face. It is ok for magic to buff oneself, but it is "cowardly" for it to sabotage a foe. Generally, the warrior magic is physical and mental health, healing, reviving, resurrecting, protection, shielding, and abjuration like protection from elements, reversing harmful magic, and shutting out mental attacks.
Surprisingly, the D&D 5e Devotion Paladin is excellent for approximating the Norse masculine magic. Its focus on courageous face-to-face melee combat, its healing and abjuration spell list, its ethic of fighting "fair", even its Charisma of personal influence and social honor are all spot on. This kind of Paladin makes a "manly" oath that is specifically about courage in battle, while all of the Devotion features work well enough.
Note, all Norse magic is "psionic" sotospeak, the power of ones own mind. So all sun elf mages wield spells that have the psionic tag, and eschew any material component. The sun elf Paladin eschews a holy symbol, or any other material component. But the spells still have a verbal component that helps focus the intention of ones own mind, and also a verbal component can substitute a somatic component. Where feminine magic is typically spoken commands, the masculine magic is typically musical chants, often with few or no words.
As the Paladin is a sun elf mage, a sun elf can be a Paladin-flavor Cleric as a fullcaster version of a Paladin. These sun elf Clerics keep the Paladin oath of courage, and can use Charisma as the casting ability, instead of Wisdom. These Clerics have the psionic tag; their spells eschew a holy symbol or any other material component, but continue to utilize any verbal component, and a verbal can also substitute for any somatic. This kind of psionic Cleric, can be of the following domains: Life, Peace, Knowledge, or Light. Keep in mind the oath of courage.
Note, the Jarl of an elf court is called a "songster", Ljodhi (Ljóði). The songster is an individual who excels at warrior magic, and possibly other magics as well.
The D&D 5e Bard is spot-on for the feminine Norse shamanic magic. Its enchantment and illusion spells approximate mind-magic (seiðr). Its divination spells correspond to prescience (spá). Its teleportation magic relating to shamanic projections of mind-out-of-body, with animal shapeshift, correspond to "form travel" (hamfar). The sun elf Bard too has the psionic tag, whose spells eschew any focus, instrument, or other material component. But they maintain the verbal component, typically a forceful command, and can use a verbal component instead of a somatic one. In other words, the verbal component can count as both a verbal and a somatic if the spell requires both.
The D&D classes that best approximate Norse magic are masculine Paladin and feminine Bard. Plus Psion, because all Norse magic is the power of a mind. However, telekinesis is rare. Examples of it are more like projecting ones mind into an object to animate the object. Likewise, telekinetic flight is rare. There is a mention of elves hovering high above the clouds. But almost every example of Norse flight involves shapeshifting into a bird, such as swan, eagle, or falcon. The sun elf psionicists are mainly: prescience-clairvoyance-teleportation, shapeshift-healing, telepathy-enchantment-illusion.
This fantasy fey elf setting has a gender-dividing culture. Where Norse culture has two genders with some fluidity between them, the sun elf culture has three genders with some fluidity between them. These three genders go beyond choice of clothing and body language. The genders include culturally assigned labor, always magical. It is possible for a woman to be a great Paladin, but she is in a mans world. It is possible for a man to be a great Bard, but he is in a womans world. Likewise, a Psion is a nonbinarys world.
In sum:
• Feminine magic: Bard
• Genderqueer magic: Psion (reflavor a Warlock)
• Masculine magic: Paladin (or Paladin-like Cleric)
The sun elf court cultures revolve around these gender expectations and the prestigious kind of magic of each.
A personal note. Of course, as a DM, I need to become any gender and every gender that an adventure story requires. As a player, my own characters tend to be masculine men. If I play a Norse Psion, he will probably be an other masculine character. Even if, the trainers and contacts will be Psions who are typically genderqueer. The situation can be fun. It can also be fun to explore a genderqueer player character. The good news is, if one becomes a powerful Psion, other people will respect it, and appreciate it.
