Sekto Springs Bottled Water Company is, as it states in title, a company that is responsible for bottling Mongo River water for sale, with Sekto being the CEO of the company. The Sekto Springs Dam on the river is owned by Sekto and keeps most of the water in, leaving the river thin and barely sustaining any sort of life by the time it reaches the southern part of the river. When Stranger asks about the bounty for a Steef head, Sekto claims he is always there. The fact that he is taking the water without any pity or sympathy for the suffering Grubbs might be why they call him "Sekto Demon."
Interestingly, the many Sekto Water ads found around the game share a resemblance with the logo of Poland Springs, a popular water bottle brand in northeastern America.