The Temple of Lies (詐欺寺) was a sect running a fake religion and a huge scam. In this temple, there is a room full of spirit tablets (called ihai in japanese) and each of them represents the soul of a deceased person. There are thousands of them here. The grieving families were paying a lot of money to that temple to keep them, and a monk was supposed to hold daily ceremonies.
Haikyo: Abandoned Japan