There are a number of "bad" gods that are worshiped- usually out of fear, or in an attempt to "bribe" the deity into not harming the worshipers. I am reminded in particular of a south American culture where the aboriginal people lived primarily agricultural lives, and had a minor evil spirit who lived in the mountains and took the evil dead.
Eventually, of course, the white people arrived, and introduced two things to the bands/villagers: Christianity and Tin mining. The people adjusted their beliefs and absorbed parts of Christianity as farming fell by the wayside and the ogre-like folklore creature took on new meaning as "Satan". The villagers would refer to worshiping Jesus and God and Mary, but the main axis of the culture was this evil blood god. The main ideal was that the god guarded the valuable metals and ores of the mountain and cave-ins and equipment failures and other calamities where his way of getting back. Proper sacraments and rituals would please the god and he would grant rich ore seams to the miners. Part of these sacraments included the construction of idols that would be placed in alcoves around the mine and granted gifts of small gems, cigarettes (which would be put in the mouth of the idol and lit), alcohol, and meat.
It was really a facinating culture, I must visit them again...