This question was more abstract and the specific situation might vary from novel to novel. However, generally speaking, completing a certain mission in the legendary prologue might trigger a plot node that would lead to the appearance of a hero. However, if the hero had been summoned before this node but did not appear, then there might be other problems such as: 1. Quest not completed: If the quest is not completed, the hero may not appear. 2. Reward not obtained: If the reward is not obtained, the hero will not appear. 3. Character has not leveled up: If the character has not leveled up, the hero will not appear. 4. Quest Restrictions: If the quest has restrictions, the hero may have problems. 5. Effects of other story nodes: Other story nodes may affect the appearance of heroes. Therefore, it was recommended to read the novel carefully to understand the specific situation in order to determine the reason for the hero's appearance.