Ichabod

Background
Ichabod Sanderling is a migratory employee. Although he's reluctant to discuss which Aperture he's from (out of fear he'll be sent back), it's clear that his home facility had a stronger focus on the supernatural.

His fear of ghosts, demons, werewolves, vampires, and assorted other creatures make him quirky even by Aperture standards, but there's a strong possibility that he has a good reason to fear these things.

He's reclusive to the point of growing his own hydroponics garden in his lab in order to limit his interaction with "outsiders." You can tell which room is his by the line of salt outside the entrance and the protective sigils drawn on the door. He makes frequent complaints to Security which go largely ignored by Trix Hunter, although she's noticed the number has dropped off since her last visit when she suggested he get some "spirit birds" to protect himself.

No one is sure what kind of work he's involved in, but he's clearly doing something to guarantee his continued existence in this version of Aperture.