Fok Yau was the first main villain whom Luk Siu Fung faced in Gu Long's stories, and apparently, the only villain to have survived. Gum 9 Ling (Book 2), Yip Goo Sing (Book 3), Bluebeard (Book 4), Wooden Taoist/Old Saber Tyrant (Book 5), Gung 9 (Book 6), and the weird assortment of pirates in Book 7 all perished, but Fok Yau was still alive (albeit hopelessly imprisoned) as of his final appearance in Book 1.
Do you think, had Gu Long lived to write more LUK SIU FUNG stories, that Fok Yau might have eventually returned to menace Luk Siu Fung and his friends again? It would have made for an interestingly elliptical coda to the saga if, in one final LSF story, Fok Yau escapes from his prison and plots revenge against Luk Siu Fung and his allies.