Heron Murmur is an agent for British Intelligence.
Like his colleague, Dorian Silk, he gets his orders from the handler known as Swann. Unlike Silk, he is far more mild mannered and agreeable. Whereas Silk might argue and fight back, Murmur would rather go along than raise a ruckus.
He is very well traveled. He has lived and operated in Japan, India, the Middle East, and Southeast Asia. He is in his mid 30s at the start of the series and has been an agent for nearly ten years, concentrating on the Far East where his skills and his background most make him an asset.
Shortly after he joined the Military right at the end of WWII, he was sent to Japan where as a junior officer, his job was mainly that of run and fetch. This would prove beneficial for his later work because to get his job done meant dealing with several different nationalities. For that reason he was assigned a translator, a young Korean woman. In exchange for English lessons, he was given lessons in Korean, Chinese, and Japanese. This ability to pick up languages would be extended to other languages, increasing the areas in which he could operate. Two others he knows are Arabic and Tibetan.
Murmur is not one to rush into danger. His grasp of languages makes him more inclined to talk his way out of trouble than shoot it out. This makes him more of a target than he would like but it fits his personality. That is not to imply that he cannot fight when it is necessary and it gets necessary more often than Murmur would like.