Kuro to Kuro to Kuro no Saidan ~Kodoku~

There is a land called Rayark. It is called a holy place, chosen by gods.
However, there are two religions dominating in this land with a long rivalry history. The one controlling the holy place is considered favored by gods.
One religion holds the spot for six decades straight, but some day prophet demands execution of the current guardian of the holy place. Her brother is labeled as rebel by prophet, and he starts his revenge.

[From vndbreview]