Mark Thaine's parents are two high ranking Starfleet Officers. His father, Jonas Thaine, currently an Admiral working within the Internal Affairs division of Starfleet. His mother, Marie Thaine, holds the rank of Commander, and heads a division of Starfleet Research and Development.

At the time of Mark's birth, both of his parents were just two years happily married. His father was a Lieutenant, his mother a Lieutenant (j.g.). Born on Starbase 16, the current posting of his parents, his younger years produced many fond memories. By the age of sixteen, however, things had changed. The constant shuffling and re-posting of his parents, both career officers, left Mark alone for most of his childhood. His never attended any one school for more than a month, and received most of his education from private tutors. His father often never saw Mark for months at a time, finally prompting one large argument which ended with Mark leaving his parents to enter Starfleet academy, ironically following in his father's footsteps. He hasn't spoken to his father since that day.

Mark Thaine proved to be an excellent candidate for Starfleet. He excelled at mathematics, engineering, the sciences, although he did suffer difficulties with the language studies, barely attaining passing grades. One major problem with Mark, however, was his discipline. Thaine rarely followed procedure. He often liked to do things 'his way', however dangerous or unorthodox that way might have been. Nevertheless, despite a number of misgivings from his instructors, Mark was seen as a talented young engineer with a lot of potential, and graduated from the Academy to be posted at Starbase 14.

The next few years didn't go well for Mark. His constant railing against 'the system' meant that he left a lot of annoyed people in his wake. His near refusal to do paperwork resulted in a number of disciplinary actions (all off the record), although his popularity among the enlisted crew was unusually high for an officer.

This trend continued to his next posting, the USS Cochrane. However, when the Dominion war broke out, Thaine's usefulness suddenly became apparent. Mark seemed to have the ability to hold ships together on a shoestring. When the Cochrane was badly damaged in a skirmish against Dominion vessels, it was Thaine's creative and unorthodox methods that he had been so berated for in the Academy and on his previous post which restored engine power and allowed the ship to escape. His personal life took a turn for the worse, however, when one of those same unorthodox repairs which saved the ship resulted in a minor overload, killing a very close friend. Consumed with guilt and despair, Mark buried himself in work, and became almost paranoid with following protocol and procedure. Following this, and to allow time for the Cochrane to be fully repaired, Mark was reassigned to the Budapest.

The Budapest was a Norway class vessel, designed for combat. During his time on board, Thaine experienced death like never before. Like so many others, the only way he could get through it was by clinging to the regs and focusing on his job.

After receiving a field promotion to Lieutenant (j.g.) as a result of heavy casualties from yet another near escape from Dominion forces, Thaine was left in command of his engineering department. Once again, the only way to get out of the situation alive was through some creative engineering and thinking 'outside the box'. Mark managed it, overcoming most of his guilt about his friend's death on the Cochrane in the process and realising that sometimes taking risks and not following every single rule and regulation was necessary, as long as the risks were justifiable.

At the end of the war, Captain Mike Talshan, commanding officer of Outpost Epsilon 4, a small outpost near the Romulan border, personally requested Thaine after hearing about his exploits during the war, deciding Thaine was just the man he was looking for to get the old station running again. Talshan was a blessing to Thaine, someone who could understand his often difficult sense of humour and someone who would give him a lot of freedom to make the repairs the way he wanted to. After a relatively pleasant three years, and one or two surprising occurrences on board the station, Thaine was reassigned to the USS Sulu, as an engineering officer. While no longer a department head, this is still a step up for Thaine, and he has all the intentions of getting his career back on track.

Mark has a very difficult personality to understand. At times (indeed, for most of the time) he can be loud, rude, insulting, arrogant and temperamental. At others he can be pensive, thoughtful, considerate, surprisingly shy, and quite charming.

His sense of humour is often the most misunderstood, mainly because of its extremely dry, sarcastic and occasionally subtle nature, coupled with melodramatic tendancies which often disguise his humour. Most of Mark's jokes are completely missed, and those that are noticed tend to be viewed in the wrong light. The main secret to understanding Thaine is to realise that nine tenths of what he says he doesn't mean. Deep down, Mark is a kind, friendly and thoughtful man, who takes a long time to trust someone. He is also a very private and shy man, and often uses his less appealing qualities, along with his difficult sense of humour, to form a barrier between himself and others.

Mark has not spoken to his father for a very long time, and it seems unlikely that he will resume talking any time soon.

Tall, with a build that would quite happily settle on muscular if he made time for food. Dark haired with brown eyes, his most common facial expression is a glare, albeit coupled with a normally missed glint of humour in his eyes.