William 'Liam' Strange is an agent with MI6.
We learn quite a lot about the history of this fellow from the beginning of the first recorded adventure, which is a very convenient introduction letting us have an idea of what brought him into the fold of the Secret Intelligence Service.
Strange was born in a tenement Glasgow in 1990, which makes him 31 years old when we first meet him. He had always been quite bright young man which pleased his mother greatly but generated a fair amount of resentment in his father, a man who was laid off from the shipyards during a massive downsizing by the government and had trouble finding reliable work afterwards, leading to a too-strong attachment to booze.
Young Strange received such high marks and praise for his intellect that he was awarded an academic scholarship to attend the University of Glasgow and followed his 4 years in collage, always staying in the top 5% of his class, with 2 more years studying law. It was two weeks before graduating with a law degree that Strange was approached by MI6.
The Intelligence community's interest in Strange came not only from his impressive academic achievements but also, and likely more so, from his fluency gained in school in French, Aramaic, and Arabic. He quickly accepted the offer of employment and started work as an analyst in the Middle East section at 24 years of age. He was surprised shortly thereafter when his MI6 section chief pulled him from his work and had him "transferred" to the Royal Military Academy at Sandhurst to obtain his doctorate in Middle Eastern studies. Another 18 months of very intensive study would follow and after that, the kind of work he was qualified to do became wide open.
This was especially true when he worked diligently to lose completely his Scottish accent and then, under instruction, grew a beard and began to learn all he could about living as a Middle Eastern man. With his studies fully over, his time to pay the government back for all his education had just started.