: I'm not super familiar with the newer Halo stuff, but I think "shield
: worlds" are a different thing from the Sphere in Eternal. As I
: understand it, shield worlds are normal-sized planets that are hollow on
: the inside (and maybe bigger on the inside or something too?). The Sphere
: is a Dyson Sphere, the size of a solar system, containing a sun inside of
Shield worlds in Halo are Dyson spheres but I think they're significantly smaller than the Jjaro Dyson, like the Halos being smaller than Larry Nivien's Ringworld.
Requiem from halo 4 is an example and there is what looks like a star in the core but its revealed to be the Didact's cryptum. (If I remember right)
Trevelyan or "Onyx" as it used to be known as, from Ghosts of Onyx and the Kilo 5 trilogy is another.
However, the Shield worlds were not weapons like the halos were; just shelters from the flood. The Ark could be considered a shield even though it isn't a sphere as it is out of range of the Array.