C1716 Puppet
Not only was the dantian the weak point of an immortal, it was also the most important thing to an immortal. If the dantian was damaged, then even if it could be recovered, it would still be worth it.
Thus, no matter which immortal it was, they would subconsciously protect their dantian.
Feng Zhi's sword was indeed aimed at Gu Feng's Dantian