A schism
Schisms are the gateways between the Cathedral of Pain in Deadside and the five serial killers in Liveside.
As described by Jack the Ripper in his diary, they are erected in both worlds "to form a link between two souls on the very brink of crossing over to the next world" and were used to send a dark soul to each of the five in order to make them immortal. Retractors are used to open them.
In the diary, there is also a drawing with the most important features highlighted (skull exposed, cords incorporated into flesh, spinal column must be exposed, internal organs removed).
It is unclear who these bodies belonged to.
Trivia[]
-a schism is a division between people from the same group due to developing different beliefs
https://en.wikipedia.org/wiki/Schism
Gallery[]
Schism from Jack's Journal
Schism conduit from Jack's Journal