Marcus is a short, middle-aged man, with an unshaven face, large patches of grey hair either side of his head and peach skin. He wears a set of glasses, alongside an olive-coloured waistcoat, cream chequered open shirt, a white t-shirt underneath and some shorts. He also wears some sandals.
Marcus is introduced as the head electrician of The Greenhouse, helping to design the Louis technology and fix different problems around the Greenhouse. He's also seen as godfather figure to Natalie Klein, who he cares for very much.
Later in the season it's revealed he's actually working in secret for Ze'ev and that he was one of the people responsible for the destruction of Naomi's space shuttle, when it re-entered into earth's atmosphere. He helps to convey many of the different hijinks around the Greenhouse, in order to further Ze'ev and Judy's plans. He hypnotises Natalie mid-way through the season, before actually trying to push Ellali and Daniel in the right direction in trying to de-hypnotise her.
Later on in the season, Marcus mysteriously disappears from the campus grounds, but is revealed to be bunged up in the Hole, being forced to carry out his missions against his own will, being watched over by Judy and Boris. Later when Team Galapagos is fully formed, he tries to convince Iftach, who has entered into the hole, to disband Team Galapagos in order to protect Naomi Reshef; Alfie and Ellali's mother, who Marcus has managed to rescue and keep alive in a stasis pod, kept within a secret chamber in the Hole.
Later during the big Greenhouse takeover, Marcus decides to sacrifice himself in order to stop Ze'evs bomb from activating, he wired himself to the bomb and threatened to destroy it, if Ze'ev doesn't stop. Ze'ev didn't and Marcus sacrificed himself.