Various Cults of the First Dimension
This scary group worships the infernal spirits of the nether.
The internals believe that the infernal spirits, demonic cat spirits, should rule over the world. They sacrifice fish because they believe that they are the spirits of the water and the nether is a realm of fire.
The infernals also like the taste of fish. The cultist hunt in packs and kill anything that opposes them. Ideally always keep a water gun on you because they hate water.
Thank me later. They are based in Cheshire, England.