Here is a strategy that has been very effective for me and has worked 99% of the time I have used it, I have used it a lot. It is basically a variation of camping the king.
Camping the king involves staying up with the king in the keep after the cut scene and taking out mobs that come his way, it helps keep the king from running off as well as concentrating your fire power. So here goes a lot of typing.
There are three essential people you need for this to work well
1. A stance tank
2. Healing monk
3. Another healing monk
Two monks are key, one to heal the tank and one to heal the rest of the part (which probably wont need it) and provide some relief for the one healing the tank.
Here is your basic uber stance tank build. You need to have high tactics, preferably max.
1. Axe/sword attack
2. Axe/sword attack
3. Bonetti’s Defense
4. Defensive Stance
5. Disciplined Stance
6. Gladiators Defense
7. Healing sig
8. Rez sig or other rez
There are two variations to this strategy and I will cover first the one that does not involve the mission bonus.
-- Primary Variation --
Well first you need to make it to the keep; this is relatively easy since it only involves mindless mob splatting. But once you get to the keep you need to stop and do a little planning and make sure everyone remembers what’s happening. First off once you clear the keep and watch the cut scene you need to stay by the king, no one run off. After the cut scene the only one who should leave is the stance tank who is going to go get one of the torches by the bonus beacons and bring it back to the group. He then just stands there and waits for mobs to come and hit him in the face, personally I like to start dancing here with the torch. When the waves of mobs come one monk keeps the tank alive while the rest of the party squashes the mobs the other monk is there to heal the party when they need it and provide some relief for the other monk when he/she needs it. Basically the rest of the party just wipes out each wave as it comes while the tank soaks up the damage. Once you see Confessor what’s his name coming, this is the last wave, he always looks like he is going to the east side but jukes back to the west, you can go down to the middle and kill him and his party and your done.
-- The super 1337 I beat the bonus, WOOT Variation --
This variation is actually much easier than the first. When you stop to plan before you clear the keep, you need to decide who is going to get the other torch and light the beacons. The beacons are on the west and east sides of the keep, the stance tank goes for one, lights his beacon and comes back to the king, the other person lights their beacon and leaves the torch there. Once everyone is back to the king the strategy is basically the same except for one thing, there will be six or so Jade that come into the keep at the beginning, these are the Jade that are spawned by the bonus, they will stay down in the courtyard. DO NOT AGRO THESE. They are your friends; they will take out the first two or three waves for you. Once they are dead everything proceeds as normal and next thing you know woot, you beat the mission and bonus.
All in all this mission and its bonus are pretty easy to beat with a good team using this strategy.