Murdoch is the caretaker of the school and is feared by a few students due to his creepy personality. Mr. Abercrombie has also used him as the shop teacher and muscle as necessary, although these are apparently not in his job requirements.
Murdoch is a tall, balding man with an eyepatch and a scruffy beard. He is missing one of his hands, replaced with a metal stump. He has a number of attachments he can place on it, including a claw, mop, plunger, and a simple giant fist. And stuff
His personality, eccentric behavior, and accent have made Mitchell believe he was "some kind of trash pirate." After Tanner gets him fired and then rehired, he becomes friendly with the three protagonists, and has been known to help them more often than harass them. Of the faculty members, he appears to be the most aware of the unnatural events and creatures of Strange Hill High, or at least the most honest about them. He still openly enjoys acting cryptic about them now and then.
He makes a hobby of shooting passing birds from the roof of the school (using a special attachment for his arm) and has shown emotional attachment to the school's rickety old generator.
It is rumored that he is the boy from health and safety it is likely since they have the same eye and the reason he has a eyepatch is to cover the scar, but it's just a rumour.