Final answer:
After killing Pluto, the narrator suffers psychological and mental anguish, symbolized by physical symptoms like sharp pains and distress from light, as he confronts his own guilt and the consequences of his actions.
Step-by-step explanation:
The narrator in the story suffers greatly after killing Pluto, the black cat. The suffering is not just physical but psychological, as he deals with guilt and the haunting consequences of his actions. The narrator experiences sharp pains and a glare that distresses him when exposed to light, symbolizing his painful confrontation with his deeds. He is confused and anguished as he struggles to accept reality. His suffering is part of a broader theme about facing the consequences of one's actions, as depicted in various texts including the mythological underworld explorations.