E. Poshtoll was Patient/Case No. 1 at the Shalebridge Cradle. Only responding to "King No-One", he was suspect in the Tallow Man Murders, brought in by the Old City Watch. He covered his disfigured face with a mask molded of wax. He was the most dangerous inmate within Shalebridge Cradle and had to be kept in The Seclusion Chamber. Doctor Sandbridge and Doctor Hanscomb's treatments were not curing him in any way.
He was "intelligent" and "highly dangerous", as Doctor Sandbridge noted. Doctor Hanscomb also noted that he managed to convince one nurse to drink his medicine. Nurse Sorrel died either from the medication, Poshtoll's attack, or a combination of both. Nurse Lovewell was spared, but had her face disfigured. Dr. Sandbridge could not figure out where Poshtoll got wax from, but it is not revealed how exactly it relates to the incident.
He was blamed for Lauryl's death by the Staff and was seemingly punished, severely, along with one other patient.