As you are fighting them, Ghi'Zard the Worg Master and four bloodthirsty worgs will walk into the room. After a conversation with Ree, they will attack, even if you haven't killed the blackguards yet.
Once Ghi'Zard and the worgs and blackguards are dead, Lord Ree and his four concubines attack. Take out the concubines first, as they're healers.
References to needing a key to access Lord Ree's chambers seem to be obsolete. If Ree is up, his door is unlocked. His respawn seems to be no more than a couple hours real time.