Claimed to be the true source of power behind the United Kingdom, Mr. Gentleman is revered by the British Library as the key to regaining the UK's dominance over the world. In the OVA, Gentleman appears to be the head of the British Library's Special Operations Division. His physical abilities are limited, but his intellect and knowledge are superior to the average man's. He is Joseph Carpenter's commander, and authorizes the missions.

In the novels, he is the first human male (His counter part is China, who organized Dokusensha), and already lived for over 500,000 years. His old man form is for preserving his life energy, if he stayed in this form, he can maybe live for around 100 years or so more. However, he is not satisfied with this, and wanted to live longer, and one of his plans is to capture Faust, who seems to be one of his more direct decedents that has a much longer life span(about 800 years old and still liking like a child). The research on Faust is not very fruitful, and he switched to finding the Gutenburg Book, obtaining a single page called the Gutenburg paper in the process and to decipher it, he released Faust to do the interpretation, which Faust took the opportunity to escape to Dokusensha, taking Yomiko with him. Gentleman is dissatisfied with his agents working too SLOWand know that the only person that can face the mastermind of Dokusensha, China, is he himself, and he switched to his young form, Young man, which he estimated to only be able to sustain for around a week, and forced his way into Dokusensha's HQ.

(Source: R.O.D Wikia)