PARTY SETUP
I won't go into exact setup details, as I'm sure you could tweak things here and there but the general build gists are as follows:
W - Dismember is good since the sword, hammer, and bows aren't affected by conditions. Disrupting Chop is useful for wurms and monks. Bring damage stances if you want, or you could help support your monk with Mending Touch and Healing Hands.
Mo/Me - Dunkoro, a reliable prot build. The Me part is for Inspire Enchantment as Kinetic Armor can be a hassle to deal with.
N - Master of Whispers, typical SS build (RH, PoF). Add in Envenom Enchantments and Rend Enchantments to deal with Kinetic Armor and the monk General.
Me - Norgu, something that eats through melee quick. Empathy, Visions of Regret, Wastrel's Worry etc. One or two interrupts. Bring Shatter Enchantment, see a trend?
Mo - Alesia, whatever she uses.
N - Claude, let him handle ALL the Blood Ritualing (don't waste your slots on Master). Plus he has some decent dmg steals and AoE.
WALKTHROUGH
I'll skip the first chunk since you should have no problems. After you've cleared the groups of hammer/swords/bows in front of the enemy ghost, park your ghost away from the altar, kill the enemy ghost, and head towards the ledge near the SOUTH bridge. Here's the part that requires luck. Like many other guides, hopefully one General will have spawned near the center so you can pull his group with a bow and dispatch them. If he doesn't, I suggest restarting as this makes all the difference in the world.
NOTE: whenever a General and his group dies (the ones that don't approach the altar), a group of Forgotten spawns and heads towards the altar. After killing the first General you should head back towards the altar and to the WEST bridge. Wait for the group of spawned Forgotten to come and kill them while behind the raised bridge.
Now space your heroes/henchies behind the altar (Earthquake can be fatal) and bring your ghost up to start the timer. Kill the 4 groups of Forgotten that arrive, then head east and kill the first Siege Wurm (EAST) that appears. Depending on how long you took to kill the Forgotten you might want to leave Master and Dunkoro with the ghost (slighty off to the EAST, so any approaching groups head for the ghost first) while you rid of the first wurm. Head back when you're done and help with whatever groups are left.
Around 4:50 a General should make his way from the WEST bridge. It is critical that after the WEST Seige Wurm appears, you NEVER get close enough for it to begin bombarding you (this allows you to leave the ghost w/o fear that he dies from the wurm). Flag you heroes slightly to the EAST as you have been doing, let the boss come up to the altar and get rid of it.
Now head SOUTH with your entire party ignoring the SOUTH Seige Wurm (yes, it'll be shooting at you) till you see the remaining two generals at the "Y" taking care of any scarabs that might have spawned. Now at this point, if one of the two remaining Generals is a monk, you should deal with that group first since it takes the longest (see the NOTE about spawns). Take care of the other general and you should be done
As an addendum, contrary to most tactics, when dealing with General groups, never go after the boss first. While their group is still alive, they have a tendency to kite. Left to their own devices, Norgu and Master should have spread enough hexes that you will eventually kill off both swords/hammers/bows even if a monk General is still alive.
EDITS: some typos/formatting, yes, I know some places should read southern.
