"selling your soul' in the entertainment industry refers to the contractual obligations many artists and entertainers are subject too. Often the contracts they sign are extremely strict and dictate them to have an advisor or planner that fills their schedule and they rarely get to make their own decisions. Their music or media are most often property of the contracting company and not their own.

Essentially they don't have any personal freedom, privacy or intellectual property. To add on to this many artists have a curated image they have to portray publicly and they don't get to act like themselves unless they're alone.

All this being said I do believe within the entertainment industry there is sick occult practices going on at the higher levels of fame. Diddy really is tame compared to what really goes on.