The large Divine Imperial City had a radius of over thirty miles. Yan Tiangang's avatar might be able to reach a place over thirty miles, but at such a distance, Semi-God Realm warriors could be safe from his attacks.
Even if Yan Tiangang were able to strike Semi-God Realm warriors across that distance, they could probably stay alive. Besides, there were so many residents in the city. A massive attack could inflict harm on people of his own family.
Therefore, Yan Tiangang did the smart thing and stopped his attacks. He wanted to pass on some divine energy and a powerful skill to Yan Hu via a special channel. Within a certain period of time, Yan Hu's abilities could be elevated, and he could go after all the Semi-God Realm warriors while Yan Tiangang would stay at the Divine Imperial Castle to remain in command. He would monitor the city and look for opportunities to annihilate his enemies.