Presented here is fiction-first, lore-heavy, cosmic-scale details that only matter if you want some deeper meaning or order to the overall cosmology of the setting. It can be safely ignored as there are no mechanical adjustments derived from these details.

The Core Premise

After hashing out the proposed lineages for Hidden World, a common thread emerged that caught us off-guard. So, we tugged the thread. It spawned so many other discussions that we felt like the effort would be a complete waste if we didn't share.

The hidden world is one where supernatural forces, 
outside mortal realms, have to interact with the 
setting through intermediaries created by altering 
humans that populate the world. Humanity is a self 
perpetuating blank canvas and raw resource.

- Dhampir are humans tainted by vampire blood. 
- Faeborn are humans altered by their proximity 
  to Fae Thresholds. 
- Haunts are humans that have returned from death. 
- Marked are the result of humans making contracts 
  with powerful beings that persist through their 
  descendants. 
- Skinchangers are the result of ancient humans 
  making pacts with primal animal spirits to survive.

This provides the boundaries for the associated 
powers in this setting and a foundation for several 
of the associated organizations.

The above premise shaped the following series of Theory Crafting articles based around the Hidden World Lineages and Threats. None of this alters any mechanics, it provides a very high-level unifying lore for "how or why" the supernatural exists.

The Forces Are Constrained, Not Just Hidden

The most significant implication is one that tends to get overlooked: if outside forces require human intermediaries to interact with the mortal world, they are not omnipotent within it. They need the lineages. That's not a convenience it's a dependency.

This means lineage communities have leverage they rarely comprehend or organize around. The Bloodline Courts, the Compact of Lines, they're not just communities managing their own members. They're the operational apparatus through which vampire entities maintain any meaningful presence in the world at all. A vampire entity that loses its dhampir population loses reach, intelligence, and deniability. The same logic applies to every lineage and its associated patron forces.

This should inform how the outside forces treat their intermediaries. Some will be protective of the lineage communities, they're an asset. Others will be extractive, treating individual lineage members as expendable while protecting the reproductive/propagation mechanism. That's a meaningful distinction that probably maps inconsistently onto existing organizational alignments.

Humans are the Only Natives

Pure humans are the only entities whose existence is not mediated by outside forces. Every other kind of being in the hidden world is, in some sense, a foreign influence expressed through a human vessel.

The setting already captures that humans are invisible to supernatural sensing but the deeper implication is that pure humans are the raw material.

The hidden world is built on top of humanity and runs on altered versions of it. This makes ordinary humans simultaneously the most endangered category (they're the substrate everything else is created) and, in some respects, the most structurally independent (no outside force has a direct claim on them).

Organizations that recruit predominantly from unaltered humans may be building institutions the outside forces can't easily infiltrate through lineage leverage. Whether those organizations understand this is a different question.

Destruction of a Patron Influence Doesn't Destroy the Lineage

If a bloodline of vampires is destroyed, the associated dhampir don't cease to exist. They become orphaned intermediaries, still carrying the machinery, still having the powers, but cut off from whatever relationship or obligation connected them to the originating force. The same applies to every lineage.

This creates a distinct category of hidden-world entity that the existing frameworks probably undercount: lineage members whose patron force is gone, weakened or deliberately severed from them. They'd have the capabilities without the alignment. They'd have the identity without the community context. Depending on the lineage, they might also have the hunger, the pull, the mark without the entity on the other end of it.

For the Marked specifically, this raises a contractual question: if the compact entity is destroyed or banished, does the generational contract collapse? Or does it persist in some degraded, possibly dangerous form?

Only the Marked have anything resembling a deliberate choice in their condition. Even then, the original contract was made by ancestors, not the current bearer. Dhampir are born into it. Faeborn absorbed it through proximity. Haunts returned without asking. Skinchangers carry a pact made by people who died thousands of years ago.

This means every lineage except the Marked are unconsenting intermediaries for forces they didn't choose. The powers are real. The influence is real. The identity is real. But the relationship that produced it was not entered into by the person currently living with it.

That's not just a character drama hook, it's a political and ethical fault line running through the entire hidden world. The organizations that exist to "manage" lineage communities are, from one angle, managing the downstream consequences of outside forces acting on human populations without consent. The Order of the Warden's Flame and the Sovereign Circle are both built around lineages defined by contracts which raises questions about whether their institutional purpose is to serve the lineage members or to serve the interests of the originating forces.

Lineage Influence Is Probably More Widespread Than Documented

Lineages propagate. Dhampir have children. Faeborn proximity to fae influence spreads. Marked contracts pass generationally. Over centuries of hidden-world activity, the realistic expectation is that a non-trivial percentage of the general population carries some degree of lineage influence of which they're simply unaware.

The Bloodline Courts' Registry and the Compact of Lines both exist in part because tracking lineage is difficult but they're formal institutions with limited reach. What's the actual distribution of latent lineage characteristics in the general population? The setting doesn't need to answer this definitively, but the question has implications:

The BUA might discover that its own agent pool has unexpected lineage distribution
The Hollow Market's interest in lineage-relevant biology gets more concerning if "pure" human is rarer than assumed
The Vanguard's threat-assessment model, which treats lineage as a marker, becomes increasingly unreliable as latent characteristics go undetected

New Lineages Are Theoretically Possible

The framework implies a mechanism:

A sufficiently powerful outside force + sustained interaction with human population = lineage

The five documented lineages suggest the most significant forces have already made contact. But the mechanism doesn't stop working.

What conditions would produce a new lineage? A new category of outside force establishing contact? An existing force finding a new pathway?

The Hollow Market's arc around infernal attunement extraction is essentially the question of whether you can engineer this process to deliberately harvest the mechanism rather than waiting for it to produce a new community.

This also means aberrations; entities that come from somewhere else entirely and don't map onto existing frameworks, are potentially a lineage-creation event that hasn't happened yet. Or has, and the lineage is so small or subtle to be unrecognized.

The Veil's Real Beneficiary Is Ambiguous

On the surface, the Veil is maintained to protect ordinary humans from threats they can't process. But if the hidden world's fundamental structure is about outside forces using altered humans as intermediaries, the Veil also protects the operational security of those forces. Humanity doesn't know it's being used as raw material and infrastructure.

Who actually benefits most from humanity's ignorance? The setting's organizations all have their own answers to this, and most of them are self-interested. But the question of whether the Veil is protection or concealment, and whose concealment, is one the setting can press on without resolving.

These are entry points, not conclusions. The ones with the most immediate adventure utility are probably the

Leverage question - lineage communities as operational assets, not just populations to be managed
Orphaned intermediary question - what happens to a lineage when its patron is gone
Latent influence distribution question - the Registry is incomplete in ways that matter

The others are slower burns, useful for campaign-level tension rather than individual sessions.