There's a door that requires 3 keys in GORO'S GREAT HALL. If you've been down there, I'm sure you've seen it. To open it, it requires you to perform some actions outside the krypt, thankfully they're not too hard to do. to get each key, you have to perform some specific action. Here are the requirements bellow:

- Mind of the One Being: Perform 10 fatalities in the Tower.

-Heart of the One Being: Perform 10 mercies in the Tower.

-Soul of the One Being: Perform 10 brutalities in the Tower.

If you don't know how to do a MERCY, all you have to do is get to the FINISH HIM/HER stage of the fight, ya know, when you can do a FATALITY, but do THIS INPUT INSTEAD

FLIP STANCE + down down down down

So L2/LEFT TRIGGER and duck 4 times. Do this at MID RANGE and you'll do a mercy.