The organization of alien species is known to humans as the Spawn.  They kill,never capture. Their primary target is Earth.  At the first war between the humans and spawn it was a quick and decisive win for the humans . . .  but then there was setback after setback.  The spawn returned and sent an armada of galactic war ships to Earth.  They nearly destroyed Earth and everybody on it.  But a group of scientists sealed them away in their own universe.  Their names are Captain N and Major Serge also adding additional  soldiers to help with the experiment.