The Rip-Off Church, or Church of Violence, is a drugs and weapon smuggling operation located in Roanapur. The church is notorious for its double dealings and is run by Sister Yolanda, and is assisted by Eda and Rico.
Their base of operations is located in a Catholic church atop a hill. Chang allows Yolanda only to sell weapons, which shows that they are on good terms with the triads. Eda is seen drinking with Revy often, and accompanies her on bounties, suggesting good relations with the Lagoon Company. Since the church deals with drugs, it is doubtful they are on good terms with Hotel Moscow.
It appears that Yolanda is aware of the fact that Eda is with the C.I.A., meaning that either her or Chang might be Eda's contact. So far there are only three known members of the Rip-Off Church, although in "Calm down, two men", several other people in sacerdotal robes are seen unloading a truck filled with "laundry" (that Rock easily identifies as drugs), proving that the Church is quite a vast organization.