Vindiami the Ancient will be an NPC and not attackable until you have killed four limestone watchers. These limestone watchers can be found inside alcoves around the zone, at
( -219, 0, -94 ) /waypoint -219, 0, -94,
( -200, 0, -61 ) /waypoint -200, 0, -61,
( -161, 0, -93 ) /waypoint -161, 0, -93, and
( -146, 0, -145 ) /waypoint -146, 0, -145. Note: Recommended to keep this one alive until you have cleared the room where Vindiami is.
Each of these watchers will also be NPCs and not attackable until you have killed four brittle bones, each spawned by examining the 4 skeletons, 2 on each side of the watcher, and disturbed them. Once all the brittle bones are killed, the limestone watcher will turn into an attackable and aggro limestone watcher, level 28^^^ heroic. Repeat this for all four watchers, and Vindiami the Ancient will turn attackable and aggro. Like most former epics he hits harder than your average heroic, but still isn't too difficult to merc-solo.