What the Codex treats as established
The visible gas envelope can be vastly larger than an ordinary star and can produce extreme luminosity, violent internal motion, powerful radiation fields, and severe gravitational effects.
Its spectrum may partly imitate a stellar atmosphere even though the true central engine is a feeding black hole, potentially of intermediate or supermassive scale.
Black hole stars are strongly associated with ancient eras of cosmic structure formation, but the Vastus does not confine them to the primordial universe.
Across a universe of trillions of galaxies, they remain rare but natural objects that may appear in more than one age or region.