There are a couple telporters in Keara's fortress, one leading to a storage area and another to the headquarters, where you'll find the boss. Just start at the bottom and work your way to the top.
Stone's fortress is the easiest one (teleporter on the north east end of the island across from the dragon cliff castle), followed by Raze (mountain across from the harbour), Broken Valley, Keara and then Kali (Rivertown Gorge).
