My ideas..

[Limelight Panda]

Instead of adding to the island, how about like a warp? Maybe when your on the mountain where Dian is, you see a... Aurora style light, and when you walk in, you get warped to where dian lives? LIke a whole new land, with different types of monsters, and if your a worshiper of dian, or brigid, you get a green/white glow and get power ups, but if your bile, or balor, when you walk in, your power goes down, making it easier to be killed by a divine creature