I’ve taken the lead on brainstorming opposition to the PCs, which will necessarily inform many of the other design decisions about the game. So I took a week and just spit out everything I could think of as a potential opposing force. I’ve broken these into two general categories: Antagonists (sentient entities intentionally opposing the PCs) and Hazards (non-sentient pitfalls that might befall the PCs). Here’s what I’ve got (so far):

ANTAGONISTS

Antagonistic Stars – The underlying assumption of the game is that the stars are more than just the balls of flaming gas they seem to be. So the stars can have their own “motivations”, and those motivations might not always jibe with our star explorers. This probably encompasses a number of other subsets: Maybe they are fearful of humans, maybe they are “socipathic” (or whatever the equivalent would be for a star), maybe they want to destroy all animal life in the universe.

Antagonistic Humans – If there are humans swinging around the universe, there are bad humans swinging around the universe. Again, this would encompass a number of other possibilities: religious zealots who think that star-siphoning or firmament-hunting is sacrilegious, rival gangs, exploitative humans who seek to siphon resources for their own selfish needs, fugitives escaping to the stars.

Antagonistic Xenomorphs – We’ve decided this won’t be like Star Wars (or Dawning Star for that matter), in that there won’t be an alien-of-the-week phenomenon going on. However, the universe is vast and almost certainly contains sentient life of some sort. What form these xenomorphs take and their motivations bears further rumination.

Elusive Firmament – If the underlying goal of the game is discovery of the fundamental shards of the firmament, maybe these shards don’t want to be found? The game isn’t just hide-and-seek but cat-and-mouse, which offers another layer of conflict entirely.

HAZARDS

Getting Lost – We’ve already touched on this some, but obviously navigation — and, by extension, getting lost — will be a key component of the game.

Gravity Traps – Strong gravity fields will interfere with star-swinging, maybe some so strong they act as an analog for quicksand to would-be explorers.

Starvation – If star explorers subsist on the power of stars, interference with that process might result in the equivalent of starvation.

Germs – Inspired by a recent discovery, microbes will still pose a threat even in the deep recesses of space.

Exotic Celestial Bodies – Black holes, nebulae, comets, etc., etc. Each of these exotic bodies can pose unique story-based obstacles for the PCs.