His weaknesses: 1)the rage-tremors. His hand and body shakes in such a manner as to debilitate weapon use 2) the schizophrenic hallucinations. He hallucinates seeing and hearing Mason, believing himself to be at least partially controlled by the deceased brother. 3) his own rage itself. This is what triggers the tremors and forces him to put down his sword, which far and away is his best weapon to use. Combine all 3 and it leaves him with power instability and mental illness.