As part of the primary quest during Act II, Chapter 6 (Princess Evangeline), after entering The Garden of the Ancients through the portal, they must first collect, then show Champion Rahvan's spirit the Death Masks of his three brothers to gain entrance to the Azunite Burial Grounds chambers, which he guards. Here's how to obtain the Champion's Mask, which you must do to enable initiation of this secondary quest. Teleport from Eirulan to north end of the Garden of the Ancients, then head east toward the Azunite Burial Grounds, Snowbrook Haven/Vai'kesh Forest Portal sign. Continue east off of the main path once your party has reached the sign, passing to the north side of a domed building, and then a Mana Shrine a bit farther on. As the path branches to the north, they'll encounter the door leading to A Frozen Crypt, which contains the Champion's death mask. Have them enter and they will have to battle a number of enemies, including an Undead Azunite Archer Hero, on their way to it of course. Once obtained, return to the Garden of the Ancients and proceed west back past the Mana Shrine, and on past the domed building, again skirting it to the north. Return to the Azunite Burial Grounds, Snowbrook Haven/Vai'kesh Forest Portal sign post and then the Garden of the Ancients (North) Teleporter. Teleport to the south end of the Garden of the Ancients, then head southwest around to the Azunite Burial Grounds entrance and speak with the Champion's ghost. Agree to help him, which initiates the quest, by destroying Letiso the Shadow Lich, who enslaved his spirit, and he'll give them some treasure plus the Mysterious (Letiso) Chant to be used to open the secret door, once they find the area of mysterious power outside the Lich's secret tomb.

Proceed down the steps into the Azunite Burial Grounds chambers and over to the northwest side of the room, where you'll see the first of two representations of the required obelisk faces sequence for unlocking the elevator switch, which will allow your party to go down to the Lich's tomb area. Proceed through the door to the east, then head down the circular stairway until encountering another door at the bottom. Open it and continue eastward for a bit, then turn south into the passageway and proceed in that direction. Open the door at the end and continue south onto the upper walkway around the large room, where ice shards are continually falling, for a few steps, then turn east at the corner. Turn south again at the next corner and continue walking along the upper walkway until they come to the southeast corner, then head west for a few steps and continue along over the upwardly curved ramp into the next area. Continue moving along the upper walkway's south side and they'll very soon encounter the second area with four symbols in the floor, which correspond to the positions that the four obelisks, which control the elevator switch up ahead, must be set to. Moving along into the next area, they'll encounter the Azunite Burial Grounds Teleporter. The path soon splits, after they reach the lower Azunite Catacombs. Send then along either of the narrow ramps past the floating heads, shooting ice balls at them. Once on the other side, left click on each of the obelisks, so that the picture on the front side of each obelisk, corresponds to the "elevator key", they passed by recently. Then left click on the lever button to ride the elevator down to the level below, where they'll be immediately beset by a mob. Rotate your view 180 degrees when you can and proceed southwest. They can also retreat back up the elevator if things get too bad. Continue along in that direction up the hill and through the columns, behind which are more faces spewing ice balls at them, until the path splits off to the south. Send them along then south path toward the shrine. As they near the tomb area, more enemies will attack. Have them clear the enemies from the area, then stand on the purple and green tree symbol, and chant the Letiso chant to open the door to the Lich's secret tomb.

Now you need to return to Champion Rahvan's spirit to reunite him with his Soulstone. The easiest way to do this is to teleport back to Aman'lu, and then from there to the South end of the Garden of the Ancients. Then just walk southwest around to the front of the Azunite Burial Grounds entrance building and a few more steps over to the entrance and speak to him to release him from his eternal torment and conclude the quest.