You'll find yourself in a small graveyard just before entering the Cathedral Ward. The graveyard's guardian? The cursed Father Gascoigne.
This is a far more frenetic fight than the previous boss, but it's winnable. The main tactic is this: keep moving. Father Gascoigne uses the Hunter Axe and Blunderbuss, usually following up a combo with a shotgun blast. Use the trees and tombstones as a shield between the two of you, and heal when you have a free moment - don’t rely on regaining health in this fight. Keep your distance during combos and deal a few blows when you can.
When he's at about 50% health, Father Gascoigne will morph into his beast form. The trees and tombstones will no longer stand in his way, so once again, keep moving. This form relies on swiping and leaping attacks. For swipes, use the same tactics as his human form. When he rears back for a leap, turn and run. You'll get a moment to attack after he lands, but you don't want to get caught in the pounce.