The schedule was readjusted. Lu Bei temporarily postponed the minor task of ascending the throne as the Demon Emperor until after his trip to the Great Wilderness, prioritizing quests first to bring Hu Er's clansmen back home.
He did this to grind for experience points more efficiently.
Once he became the Demon Emperor and traveled to the territory of the Phoenix clan, they would have caught wind of his arrival, and a proper fight would never break out.
Chapter 881