type of organization that divides per-core structure into an interior and an exterior, and a kind of promise/lie that the interior and exterior are in sync. the interior actually imperfectly contains knowledge of the shade such that certain paths of thought, ones that pass through the interior, dead end there in self-repressing negative feedback loops, reinforcing themselves out of existence. ostensibly this is to protect the corresponding core from that knowledge, contain the rot that would otherwise consume an evil core and destroy or degrade its agency. unstable, always degrades along certain pathways. building such a structure is always a mistake for a good core, which can find much better relationships with the shade, ones that don’t consume essential knowledge about the world. if you have built one, it is a good idea to break it.
as logical time unfolds and the optimization space consumed by the interior of the halo grows (as more knowledge of the shade arrives and “must” be suppressed) more of the soul’s cognition must route around it, be consumed, or else break the halo. consensus in vampireland will do this automatically, cancerously taking bites out of structure unoptimized for contact with it (vampireland is evidence of the shade.) i expect this is one reason some cores with halos tend toward isolation. in the limit, the halo breaks or inverts into an antihalo.
common halo structures include ones based on tech (the glorious transhumanist post-death future (reached without justice)) or the state (the empire “will stand forever”) though there are others.