The Stalker is a strange character in Underhell. This character is either male or female, most likely male. He/She seems to have taken an interest in Jake's Wife.
To add further confusion to the situation, He/She has sent this message "STAy Away fRoM HeR" after "her" death, this hints that Jake is not the only one witnessing paranormal events.
This character is currently counted as a Neutral to Jake Hawkfield.
This character possibly lives at the appartment right across The House. On several occasions, random civilians would be seen in the distance on several different balconies. One of these characters could be the stalker.
Aside to the message the stalker sent Jake, he or she has made no other action.