Use the 2H axe and do a charged swing at him, when he's near the edge, and he'll fall off. Thing is, you really don't have to beat him to advance. In fact, beat the Blood Starved beast, leave Old Yahrnam, come back from through the prison area instead (beating Darkbeast Paarl), and you'll basically come up behind him where he'll instead talk to and be your friend, provided you promise to stop killing beasts.









