As for the other few sword techniques...
During the Dongying period, Su Chengyu used the Sky-splitting Sword to unleash the Sky Opening Technique.
After that, Su Chengyu never used it again, not because he forgot the sword momentum, but because the amount of power from the Heavenly Dao imbued in it was too little.
At that time, the feeling wasn't clear, but now it seems that being able to swing that sword back then was largely due to borrowing the might of the Sky-splitting Sword, and perhaps even a significant part of Ye Qingci's power.
The sword technique remains, but even Su Chengyu himself finds it extremely difficult to replicate the Sky Opening momentum from the Dongying period now.
Then there was the Sealing God Style unleashed underground in Qinling.
This sword was initially swung by Su Chengyu by leveraging the suppression against the Demonic Path hidden within the Dragon Slayer Sword, creating a technique initially very similar to the Slaying Monster.
