Good Kingdom politics
by Marc SaindonAside from taking inspiration from Asterix, Robrenn could be a hotspot for Fae activity of the Good Kingdom, with the Robrenn versus Orcs & Goblinoids merely being an extension of the politics of the Fae Courts, with the Seelie supporting humans & demihumans, and Orcs having uneasy pacts with the Dark Lords of the Unseelie. Whenever the Unseelie expand their influence, the region undergoes the Darkening, which makes everything look like it was filmed by Tim Burton: shadows grow longer, trees grow more twisted, animals are more menacing, it's always cloudy, and Orcs can walk in daylight without penalty. Planted crops fail, but mushrooms have an easier time to grow. The influence of Unseelie could also further cement the culture of Celtic Orcs (or "Orcos"), especially as they consume a lot of the goods produced by Robrenn through pillage.
The Light Fae aren't necessairly good, as they see the Confederacy of Robrenn as chess board (or Fidchell board in their culture) for their own entertainment, with various pieces being analogous to the town emblems (rooster, boar) , and when the Unseelie are inactive, they busy themselves on this decadent game with elaborate rules with consequences to the rest of Robrenn. To make a piece advance, one Fae might first set up a fight between two villages, for example. Or they invite a Bard to play in their courts, only never mentioning that he can only leave after 2 centuries once he's there.
The King's mandatory quest (every 12 eyars) might be part of the pact meant to placate the Light Fae with "entertainment" or services.
Further adding to the conflict is the Triskelion - sort of the Triforce with serial numbers filed off that looks like a big bling bling golden medallion. The Seelie have one part of the Artefact, the UnSeelie have another. Humans have the third part. However gains all 3 parts... you know the drill. Traditionally, the Human King would ceremoniously take a Fae Princess as wife (a bit like the Doge of Venice "would marry the sea" by throwing a ring in the water), giving the king a 2/3 claim over Robrenn's sovereignty. Intrigue could happen (both Fae Courts ally, the new king is seduced by the Unseelie queen, or someone steals the Triskelion part).
(Image from: https://www.deviantart.com/noflutter/art/Light-Vs-Dark-595750887)