A horde dies only if all its bodies are destroyed. If any body escapes, the horde immediately begins to rebuild. It can create a replacement body (or increase the size of a physically inactive body) at the rate of 1 Hit Die per turn. The horde cannot use ESP or telekinesis while creating or increasing a body’s size.
However, the horde life force can control bodies only within an area 100 miles across. If one of the horde’s bodies is taken outside this range, that body becomes a mindless thing and dies in 1-10 days.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.