A tupilaq is an avenging demon in Inuit tradition, fabricated from skin and bones and blood to seek and destroy the shaman's enemies. In Fortitude, Henry has a tupilaq fashioned with his own blood in an attempt to destroy the evil spirit that is infesting Liam Sutter. It's one of the many ways that the community of Fortitude is trying to come to terms with the mystery that is tearing them apart. Though while there are increasing hints of a supernatural cause for the evil at Fortitude's heart, I still maintain that these clues are similar in nature to those in season 1 of True Detective; possible pointers to a supernatural cause, but only in the minds of people. I still maintain that the answer is a prehistoric brain-affecting plague, and the real monsters are not spirits or demons, but people pushed to the brink of their own madness.
One such monster is Frank Sutter. So desperate is he to prove that his boy is innocent that considerably gruesome screentime was dedicated to him torturing Markus; only the timely intervention of his wife Jules spared Markus from losing more body parts than a fingernail. Calmly she soothed the monster, desperate to at least preserve this last shred of humanity within her rapidly fraying family.
The next uncomfortable scene was the brain autopsy of Shirley Allerdyce; an unsettling scene filled with face peeling, skullcap removing and very uncomfortable looking characters. The horror imagery continued with the increasing isolation of Fortitude, a horror trope used to good effect elsewhere and seems to being built up to slowly but invariably.
It's a pace that still continues to unsettle, yet it's not stopping people watching. Interestingly, Fortitude isn't getting the majority of its viewing figures from live viewing. The consolidated audience is almost three times its average overnight rating, making it Sky's biggest homegrown drama to date. 1.3 million people are watching Fortitude on average, and while it hasn't officially been recommissioned, indications suggest it will be.