I'm sure this is too late for those who requested it but here is my solution once inside the crypt...

  1. Defeat Rotha (NW on map) for one of the crystals.
  2. Find second crystal in eastern tunnel chest.
  3. Place the crystals in the provided pedestals near the southern locked gate to open it.
  4. Read Jake's mind for a clue as to how to defeat him - OR - find a book in a chest in the SW corner - OR - ...
  5. Click on the Tombstones or Wall Plaque of those that Jake killed. They will rise from the dead, very angry, so kill 'em.
  6. Once all four of Jake's victims have been killed, again, only then can you kill Jake.

Note: in the eastern tunnel there are two Malachite Ore Veins north of the platform edge where the poisonous sewer begins. Jump to safety and save without pointing on either of the veins. Reload as desired to get the best results.

[Linked Image]
[Linked Image]

Lord John Whorfin: History is-a made at night! Character is what you are in the dark!