Alexander 'Xander' Ross is an agent with MI6.
He is a new one - a quite new recruit because he has tired of his previous line of work and wanted to do some more meaningful and interesting and exciting and, well, different.
His old job that he wanted to leave behind? He was a cellist.
You are reading that correctly. He was a cellist.
When we meet him in the first recorded adventure, again, to be honest, the first adventure ever for him, he is just landing in New York City to perform at Lincoln Center and he has gone many hours without sleep, has a rotten headache from the long flight and a long delay from Heathrow, and he is not that anxious to be performing a brand new piece of music with a conductor he has never met and other musicians he knows nothing about.
Ross is quite well known in the symphony business, known as the Dark Cellist, "that musician who has singlehandedly popularized strings to such an extent, that cello is now viewed as the coolest instrument to play in our grammar and high schools," to quote that conductor. Of course, the role of that 'Dark Cellist' is just a persona according to Ross, one prepared for the stage and not at all like the Ross the outside world sees complete with "a hard intense sexual gaze [he] used all the time - a look that had felled thousands of female fans".
Ross is honest enough with himself to know that as popular as that Dark Cellist is with the audience, especially female members, it was something he regretted creating. Every woman he meets expects the same harsh "love-em-and-leave-em" near-brute they imagine they see on the stage. He knows it is not really him and he has tired of that fellow.
It is a Xander Ross who enjoys his music but has found the life of performing it not as satisfying as it used to me who looks for something else to do with his energies and surprises everyone, including himself, by applying to MI6.