trolls KNOW that the soul hangs around as a disembodied spirit postmortem so there isn’t really any need for them to speculate about an afterlife but what they CAN speculate about is stuff like “should i eat dead people”
on a more serious note i guess things like “what should i do with a troll’s dead body to appease their ghost” are important spiritual questions in the troll mind. which is probably why the burning of the sufferer’s corpse to ashes was such an important part of his execution and his subsequent history