I saw that video on "Supernatural Stories" channel, I think. Some of the testimonies there sound like dreams to me, but this one certainly had multiple people and dates to add veracity. The founder he's talking about was Anton LaVey, who was quite a con man. He got ideas from another "founder" and con man, Aleister Crowley. LaVey was more organized and a better money maker though.

Edit; Wrong guess, it was the link u/17JCsCrib26 posts below, "Top Satanist Attacks Believers."

I saw that video on "Supernatural Stories" channel, I think. Some of the testimonies there sound like dreams to me, but this one certainly had multiple people and dates to add veracity. The founder he's talking about was Anton LaVey, who was quite a con man. He got ideas from another "founder" and con man, Aleister Crowley. LaVey was more organized and a better money maker though.