The Water Curtain Skyflower Gu was a Rank four Gu. Once used, it would turn into a giant spherical water shield. The defensive strength of the shield was extremely good and it could even resist attacks from Rank five Gu. However, it had a big weakness; it couldn't be moved and couldn't be stopped. The water shield isolated the inside and outside world, so even the owner couldn't freely enter or exit. Thus, this was used by many forces to protect their territories.
Fang Yuan was not familiar with Spring Autumn Cicada.
In his previous life, he died by the besiegement of the righteous path after just having succeeded in refining the Spring Autumn Cicada; he simply didn't have the time to experiment with it. Also, Spring Autumn Cicada wasn't his vital Gu at the time and this characteristic hadn't revealed itself.
In this life, his cultivation was still low, so he didn't dare to randomly let out the Spring Autumn Cicada.