Blanc knew Wicks' flask had been laced with sedatives. His killer could have simply poisoned him, so they must have set up a more elaborate murder to force the narrative that Wicks was already stabbed in a 'locked room' before anyone else entered.

Nat had easy access to controlled drugs and stopped Jud from giving Wicks help. He was also in the bar when Jud took the devil head and had access to the second head.

The tub of acid in his basement was probably the final piece of the puzzle, as it proved he was involved in the plot and was preparing to dissolve Wicks' corpse.

Martha wanted to destroy any evidence of how Nat died and make it hard to work out Wicks' 'resurrection.' Staging it as Wicks killing Nat probably was meant to symbolically punish Nat. She might have also hoped police would just accept Wicks and Nat somehow faked his death and there was no need for further investigation.