Unfinished masterpiece

Submitted for the concept101 challenge!
The brief was ‘unfinished masterpiece’ with an emphasis on the storytelling aspect.
The story depicts an occult wizard attempting to complete the summoning of a powerful demon, Abaddon, from the abyss, but he’s ultimately stopped before the final act by armed police.
In the scene you can see where he has plotted his masterpiece, with supporting details to suggest how much effort went into his work, filling the abandoned pool with barrels of blood, covering the walls with magic texts, etc…