It's in the large reddish area where the named demons are.
From the brazier near where Cet's tomb is: go east. When you T-intersect, go south, then east again up the ramp. Turn to the left at the top of the ramp. On the left will be a door. Inside is a named demon. Fight him and when you defeat him, a pit will open in the back. He'll also drop a key which you'll need later.
Drop down the pit and follow the tunnel to where it opens up over a walkway and a ledge on the other side. Jump over to the ledge, and take the lift up to the next level, then catch the next lift all the way to the top.
From that room, proceed east (?) again. You'll be on a platform way up near the ceiling. In a sacrificial dish there, you'll find the heart. Grab it (make sure there's room in your inventory) and backtrack to the Black Fire urn, and "Use" the heart there.
Make sure a female uses the heart!
-Sazerac
|