The colored stone tablets are supposed to give you some hints for solving the puzzles, but in reality they're of little help.
Go to the temple in the bandit camp and find the door that Raven disappeared through. Use the tablet Quarhodron gave you/the door and it'll open.
First chamber[edit]
There are five buttons on the wall on the left. If you press any in the wrong order, spikes come down and you die instantly. (so save) The correct order is: leftmost button, rightmost button, center button. The hint is on one of the fire coloured tablets that says "We, the last three of the council of five, have set up traps and sealed the doors of the temple so the sword never again sees the light of day" (last 3 - 3 figures on the left button, traps - spikes on the right button, light of day - sun on the middle button). A door opens.
Second chamber[edit]
Kill the three stone sentinels. There are many identical looking exits in this room and all but one mean certain death. The hint on the blue tablet is "Khardimon made the second trap, only he who follows the way of light can pass it". This rather cryptic hint may refer to your will o' the wisp amulet, if you activate it it can find the weapon that's in the right exit. The will o' the wisp could get stuck on the exits though, but eventually it'll get there. Or you just walk right into the exit directly on the right.
Third chamber[edit]
Light a torch or use a light spell. Stay away from the greenish tiles. (again: instant death) After the tiles, go through the gate on the right.
Fourth chamber[edit]
This chamber has floor spike holes all over and an island in the middle. In the corner is a bandit with loot. On the walls are many levers. They all do the exact same thing: open the door and trigger the trap. There is no special lever. (this has been tested) What there is, is the ghost of Rhademes. Stay on the island in the middle and exhaust all dialog options. No matter what you ask him to do, he'll pull a lever and trigger the trap. He's already dead, so it makes no difference to him. The door opens.
Fifth chamber[edit]
There are six stone sentinels in this room. You probably saw it coming: they'll come to life before you reach the door on the other end. You can fight them before they activate.
Final chamber[edit]
When you get to the chamber with Raven, you'll see him praying to a coffin at the end of the chamber. You can walk up to him and have some conversation before you kill him, or you can just go straight to killing him. The latter would give you some advantage as he doesn't use ranged weapons. If you'd rather not fight Raven at all, summon either 1 skeleton, about 8 wolves or about 12 goblin skeletons before you go to Raven. Whichever you pick, never mix summoned creatures because of infighting. Now walk towards Raven, cast ice block and watch as your summoned creatures finish him. Obviously you could also attack him yourself while he's frozen instead of summoning creatures.
Behind the coffin that Raven was praying to is a door with a button. Press the button and you'll find a teleporter behind it that takes you back to the bandit camp. Talk to Thorus and use the teleporter to go back to the water mages and tell them everything. Before you leave Jharkendar, use the teleporter to the canyon and tell Greg the pirate about Raven for 1000 XP and 500 gold.