The three men's life essence had completely resolved into the blood, became nourishment that Su Bai needed and was totally absorbed by Su Bai.
That was what vampires do. That was why vampires were terrifying.
Guo Cheng's self-destruction was a threat to Su Bai because it almost blew him away and he had to turn into blood sticking onto the door frame.
If Guo Cheng had made that move in the beginning, with his seven blood swords all in good condition and his soul sword as guiding, Su Bai could never stand a chance. But Guo Cheng didn't. He didn't think he could lose. When he realized that he was losing, it was already too late.
He had lost almost six blood swords of his origin while Su Bai had absorbed his lost origin, and his soul sword was worn by Su Bai's evil energy. In that case, Guo Cheng's self-destruction had become nothing more than a wishful thinking.
It even somehow helped Su Bai as a great opportunity for evolving.
