Fable 2 Guide - Temple of Shadows
The Temple of Shadows, the diametric opposite to the Temple of Light, is stationed in Rookridge on its own island, reachable via a lengthy bridge up to the impressive structure. Once at the front gate you'll meet one of their members, a Shadow Worshipper. They have a rather tame entry test, though that is just to get inside the gate and not to join them. Simply crunch and swallow the chicks using the expression that appears on the D-Pad to impress and astonish him, and grant you entry to this foreboding place. You should note that this will give you 25 evil points and is unavoidable. This completes the Temple of Shadows quest. Those looking for the secret items can now venture inside and get them, then do the Temple of Light quest with only a minor morality hit.
To participate in the Oakfield Massacre however you still need to make your first sacrifice to the temple in Sacrificing to the Shadows.