Originally Posted by RaZeDieFox
Make sure you kill all 9 officers before they are turned into allies, and then kill Sun Wukong as soon as he appears. Just be sure you're not killing sorcerers before you kill the enemy officers they control. To be safe you could always kill each of the 9 officers without killing any sorcerers, just to be sure you get them all. Also at the same time, remember none of your allies can die.
I too am having a problem with this treasure.
However, I've noticed that the sorcerers won't appear until you've killed each of the officers they control once. And the final sorcerer won't appear until you've killed each officer once AND Sun Wukong, so I don't think it's possible to turn all 9 officers into allies until Sun Wukong is killed.
I've done this level about 8 times now and still no treasure. :/ Allies are surviving, officers all dead, but nothing! Also I've changed characters many times so I can't be using one that stops something from triggering.