Ahriman

You worked as a private reporter, investigating mysterious and mystical stories. One day, you heard rumors of a cult hidden deep in the forest. Sometimes, the cult's representatives would recruit members. Taking on a photographer as a partner, you were introduced to the cult through this person. At first glance, the people seemed friendly. You realized their friendliness was feigned. You began asking questions about who exactly the locals worshiped.
"We call this god Father or Papa," explained the old woman in whose house you were housed. She recounted rituals that seemed innocent.
You continued digging. Under the pretext of exploring the surrounding area, you and your partner combed the forest. And, to your horror, you found a ditch filled with rotting human remains. The thrill of this discovery overwhelmed you. Returning to the house, you began packing, but before you could even step outside, you were knocked unconscious.
You woke up with your hands bound and gagged in a deep shaft. Someone from above said, "We don't gather people. Our commune is closed and strong. But we do need sacrifices. Our god is Ahriman."
The elder told a story about a god who was supposed to cast the world into darkness.

• And now he will eat you...
  You are left alone.
  You didn't believe in gods, but you believed in madmen. While you were trying to free your hands, something moved in the corner.