Blackbeard's descendant had a very tragic backstory. He had nothing to do with the Cursing Sect at all, and he just lived here in seclusion. However, the poison that Zangila released had infected him as well.
Although Blackbeard's descendant had become an undead, he could still retain a sliver of consciousness because he had the Hero's Bloodline. He never attacked players of his own accord, but if a player attacked him, he would fight back, tooth and nail.
When Li Yi saw Blackbeard's descendant, the latter was being surrounded by a group of spirits. The two sides were deeply embroiled in battle. Of course, considering how powerful Blackbeard's descendant was, the spirits were naturally no match for him. With every swing and slam of his sledgehammers, he would kill one spirit.
"Zangila, you mad monster, I'm gonna kill you, I will…"
Blackbeard's descendant finished off all the spirits but he kept howling out angrily, yearning for revenge against Zangila.