Lords of the Fallen (2014)

You can't get this until after you beat the Beast Boss , as the room containing the sword will be locked until then.

After you beat the beast , go back into the citadel, through the large doors, and down the stairs and through the small door.

In this room look on the left wall for a newly opened door with some stairs going up, there are some heavy hitters here so be aware of them. Go up the stairs and through the door ahead you you clear out this room and the cursed sword should be here along one of the walls, (looks like any other pick up in the game little red crystal)

Next go to the graveyard where you fought the worshipper boss, as you enter you are looking to you left for an open grave beside a tree, I'd say 2 O clock if looking from the entrance of the grave yard its around the middle of the left side., before you press to investigate and bury the sword be sure to clear out any enemies first as another will spawn when you bury the sword.

Kill the ghost and pick up the sword that spawns.