Alexander Martin was a Kanatian con man. He was also a trained medic. He knew Jack Harkness back when he was a con man.
While working as a con man, Alexander impounded Jack's ship while pretending to be a customs official on Balthazar. He later gave it back because "it didn't suit [his] purposes. Alexander again encountered Jack while pretending to be a health inspector at a Spice Bazaar on Velecerol.
He laid low on Earth for his retirement, living in Cardiff at Mercy Hill Care Home. (PROSE: The House That Jack Built)
Alexander was trapped in St Helen's Hospital during the the All-Night Zombie Horror Show. When the "zombies" broke into the hospital, his nurse ran off, and Alexander was left to fend for himself. He attempted to deflect the attention of an approaching zombie, whom he nicknamed "Slug-Face" onto a "fat woman" trapped in her wheelchair 10 metres away. His plan didn't work and the zombie continued to make a beeline for him. Alexander raised his hands, ready to go down fighting, but the creature brushed past like he wasn't there. Realising he wasn't going to die, Alexander couldn't help but cackle at the sheer grotesqueness of the spectacle. (PROSE: Bay of the Dead)
A few days later, Jack Harkness hired him on a freelance basis as Torchwood Three's new medical officer. (PROSE: The House That Jack Built)
Personality
Alexander considered himself a battler, a fighter, stubborn and determined and living on his own wits. He was the type of person who held a grudge. When his nurse, Ben, ran off during a zombie attack, Alexander made a mental note to hunt down and decapitate the "tiresome little shit" if he managed to survive. He seemed aggressive and had a lot of pent up anger. Facing the inevitable was not in his nature. He always envisaged that his death would be comfortable and painless, planning to expire gracefully between silken sheets with a beautiful woman by his side. When approached by Slug-Face, he attempted to deflect its attention onto a "fat woman" trapped in her wheelchair. Faced with death, he was prepared to go down fighting. (PROSE: Bay of the Dead)
Appearance
Alexander was bound by a wheelchair and had rheumy eyes. Jack described him as an "old curmudgeon" and stated that "time had not been kind". (PROSE: Bay of the Dead)