If you're ever having trouble with the Outrider Knight... (possible spoilers)

At the bottom of the church leading into the Road of Sacrifices there's the Outrider Knight with the Irithyll Straight Sword, and he's a pretty tough cookie. Last time I fought him, funnily enough I managed to get him to fall down the elevator shaft to his death. I still got the sword drop, too! Just a friendly tip.