A fictional world is more than just the physical setting and the biological and psychological nature of whatever inhabitants it may have, it may also be filled with people, each with their own personality and history, some of whom may have a profound impact on that fictional world. There are times when a world's future may hang on one person's decision.
So, the question: Are questions about an individual (who may be fictional, or who may be a real person placed in a fictional situation) in a particular world on-topic?
This could be "What would X do here?" or "What sort of person would I need to do Y here?" questions, or other questions involving a specific inhabitant of a world, whether defined yet or asking for a definition.