In which episode did the old nine men and eight lords die?

Not dead. Eight lords are the eighth door in the Laojiu family, and there are three subordinate doors. His specialty is Qi Tiezui, a fortune teller. In Old Nine Doors, Qi Tiezui, the Eighth Master, died suddenly at home the next day after receiving instructions from Wu Laogou. In fact, Eight Lords didn't die. He just ate the so-called elixir of life, which formed the phenomenon of suspended animation, so as to erase what he shouldn't have left and destroy what he shouldn't know.