Science Fiction & Fantasy Stack Exchange is a question and answer site for science fiction and fantasy enthusiasts. It only takes a minute to sign up.
Sign up to join this community
At some point we are shown a battle between the main character and one of the bad guys... but all the others just seem to run away, and it's never shown what happens to them.
It is possible that as a kind of hive mind, one was "representative of the whole", and thus beating/killing him had effect on all the others, but it appears that at least one of them had survived, so this seems unlikely.
Assuming we take the film's official novelisation at its word, the answer is that the Strangers (whose race only numbered a few dozen) all died out at the end of the film, killed by the rotation of the world into the sunlight.
From the book's prologue
Which was sufficient. Until they chanced upon a small blue world orbiting a minor star. The planet abounded in two elements that were lethal to the Strangers. One was water. The other was sunlight.
Murdoch takes control of the machine
A straggling group of Strangers advanced warily, eyes fixed on Mr. Book’s floating corpse. Murdoch understood they were helpless now. The city was no longer theirs to control. Nor was he.
One by one the Strangers scurried back into the shadows like frightened silverfish. Within moments the streets were completely deserted. A ghost city.
And from the book's final page. Note that hiding in the shadows is insufficient to save Mr Hand
Suddenly sunlight beamed into the corridor as Murdoch stepped away from the door — driving Mr. Hand back like a panther fleeing fire.
Weakly, the Stranger stumbled back into the protective darkness. When he reached the stairs he saw the muddy lake bubbling up.
Trapped between water and sunlight, Mr. Hand crawled into the shadows and curled up to die . . .
The one left alive had been imprinted with the hero's own memories, thus making him different from all the rest. The ending hints that the rest are either all dead, or otherwise irrelevant, though no hard proof is offered.
The Strangers scurried back into the Under City where they were safe from the sunlight. Mr. Hand was already dying from the effects of a Human imprint when he was caught in the sunlight.
A few pages before the end of the Novelization:
Murdoch understood they were helpless now. The city was no longer theirs to control. Nor was he.
One by on the Strangers scurried back into the shadows like frightened silverfish. Within moments the streets were completely deserted.
