Great news: One Reborn might very well be the easiest boss you'll face in all of Bloodborne. The trick is to run right at it as soon as you start the fight, and turn to run up either set of stairs to its left and right. On the second floor, take out the six casters, hit the One Reborn with a drop attack, and just start swinging. Avoid the easily-telegraphed area-of-effect attack and gore showers, and you'll breeze right through this fight.
Check out the video above to see how we took down the One Reborn, and stay tuned for more Bloodborne boss guide videos.