You rush the huge skull-spider and hack away with the sword. At this distance it's impossible to miss. Even when you hit with the flat of the blade, the legs crunch under the impact. Ichor flies around you as the thing tries to back away on its intact legs. You keep beating at it, driving it back, until the blade strikes the human skull it has for a head.
The bone cracks open under the blade, releasing a shadowy vapor that disintegrates with an icy blue flash as it touches the sword. The skull crumbles into dust. The giant spider body follows suit, falling apart into thousands of smaller spiders that scurry away from the light.
"Now they're just spiders." The voice in your head carries a tone midway between satisfaction and exasperation.
You turn to see what's happened with the guard. The blank, unblinking stare tells you everything you need to know. His chest and throat had been slashed, and if he hadn't bled to death, the impact with the ground was enough to break his neck. The sight of his body makes you think.