Tobias Zed was the Walker Expedition's archaeologist. He laboured at discovering the nameless script found on the planet orbiting the black hole designated K37 Gem 5.
Biography
Toby was in the control room when the quake came in and soon after was told to check the rocket. He explained to the Doctor and Rose what they were looking for. Zed kept hearing the voice of the Beast, which eventually possessed him. While possessed Toby went outside onto the planet. Eventually Scooti Manista, another member of the crew, heard him leave. She went to investigate and eventually found him outside. He motioned for Scooti to come forward. She continued raising her hand towards him as if hypnotized. Eventually she begged him to stop. He grew angry with her and began breaking the glass. Scooti tried to excape but he had managed to trap her. Soon the glass was ripped apart and the screaming Scooti was pulled out to him by the rushing air. Toby then rushed to join the others to avoid the hull breach. Toby told no one that he killed Scooti. After Ida and the Doctor went down, he was repossessed and he then possessed the Ood and they began killing off the crew. (DW: The Impossible Planet)
Through "freed", the Beast remained free to possess Zed. As the Walker Expedition rocket left the planet with Rose Tyler on board, the Beast manifested itself in his person. Rose unbuckled his seatbelt and used the bolt gun to smash the window. An emergency window prevented the ship from de-pressurising and Toby flew through space, into the black hole. (DW: The Satan Pit)
Special abilities and features whilst possessed
While the Beast took him over, Toby's irises turned red and the script appeared on his body. He could survive vacuum unscathed (DW: The Impossible Planet), spoke with the voice of the Beast and could issue flame from his mouth. (DW: The Satan Pit).
Personality
Toby Zed had a quiet manner, though Rose also upbraided him for his dramatic nature. He revealed signs of mental instability in some of the graffiti he had written on the base walls: fragments of Krop Tor and possibly (unless someone else wrote those words) the message WELCOME TO HELL. While attempting to use the personal fears and weaknesses of the Doctor, the crew and Rose against them, the Beast revealed to the others that already into his twenties, was still a virgin. (DW: The Satan Pit)