Listening to Mayhems brand-new black-mass Esoteric Warfare I was browsing tru the artwork of that very record and discovered the awesome art of Zbigniew M. Bielak (only the last pic is the cover and belongs to Mayhems record). Other bands he did some art for are Watain, Ghost, Vader and Absu.
"The album’s cover art is part of a single, large piece that was separated into 12 or 13 pictures; it was made in collaboration with Ghost and drawn by Polish artist Bp Necropolitus Cracoviensis Zbigniew Bielak II and inspired by the album’s lyrics and themes. A Nameless Ghoul said that because the album deals with the Antichrist "we knew there was going to be a baby on the front cover. It also represents the paradox of inborn evil, of being very innocent and very vulnerable", and said that it is a pastiche of the film Amadeus." wp