Leaving in Exasperation

The process of ascending to the Celestial King Tier was that of germinating and growing one's Celestial Seed, especially during heavenly tribulation. Even though this was dangerous, it was the best opportunity for the Celestial Seed to grow quickly. This was because heavenly tribulation contained the power of heaven and earth, the most useful nutrient for Celestial Seeds.

Once heavenly tribulation passed, the growth of one's Celestial Seed would become unbearably slow. In fact, it wouldn't be strange to come across people who needed an entire epoch to advance to the First Heaven.

Even though Yu Wudi was a monarch star, his cultivation speed at the Celestial King Tier would also be severely limited. Thus, if he lost this opportunity, perhaps he would need to spend 100 million, one billion, or even 10 billion years to make up for it.