Even though the fish bird had created its True Path, Shang still didn't have more issues than before.
The fish bird was a Late Beast Lord. A couple of techniques from the Fourth Realm didn't make any difference.
The two of them continued fighting for about five years.
It seemed like creating an Impose wasn't very easy for the fish bird, and it would probably need another couple of decades to create one.
So, while the fish bird stopped improving in the fight, Shang continued to become stronger.
In comparison to the fish bird, Shang was already working towards comprehending something that would allow a normal warrior to reach the Seventh Realm.
After another five years, Shang wasn't on the edge all the time. The fish bird was still insanely fast, but his usage of his sword had improved tremendously.