Captain Nemo's origin

Or Who is this Nemo guy?

Several people have come to this site in search of the origin of Captain Nemo
We know he is a character in Jules Verns '20,000 Leagues under the sea' but, in 20,000 leagues under the sea his history is left mostly a mystery, for a more detailed account you have to read Jules Vern's 'Mysterious island'
Here's the passage:

Captain Nemo was an Indian, the Prince Dakkar, son of a rajah of the then independent territory of Bundelkund. His father sent him, when ten years of age, to Europe, in order that he might receive an education in all respects complete, and in the hopes that by his talents and knowledge he might one day take a leading part in raising his long degraded and heathen country to a level with the nations of Europe. From the age of ten years to that of thirty Prince Dakkar, endowed by Nature with her richest gifts of intellect, accumulated knowledge of every kind, and in science, literature, and art his researches were extensive and profound. He traveled over the whole of Europe. His rank and fortune caused him to be everywhere sought after; but the pleasures of the world had for him no attractions. Though young and possessed of every personal advantage, he was ever grave--somber even--devoured by an unquenchable thirst for knowledge, and cherishing in the recesses of his heart the hope that he might become a great and powerful ruler of a free and enlightened people. Still, for long the love of science triumphed over all other feelings. He became an artist deeply impressed by the marvels of art, a philosopher to whom no one of the higher sciences was unknown, a statesman versed in the policy of European courts. To the eyes of those who observed him superficially he might have passed for one of those cosmopolitans, curious of knowledge, but disdaining action; one of those opulent travelers, haughty and cynical, who move incessantly from place to place, and are of no country. The history of Captain Nemo has, in fact, been published under the title of "Twenty Thousand Leagues Under the Sea." Here, therefore, will apply the observation already made as to the adventures of Ayrton with regard to the discrepancy of dates. Readers should therefore refer to the note already published on this point. This artist, this philosopher, this man was, however, still cherishing the hope instilled into him from his earliest days. Prince Dakkar returned to Bundelkund in the year 1849. He married a noble Indian lady, who was imbued with an ambition not less ardent than that by which he was inspired. Two children were born to them, whom they tenderly loved. But domestic happiness did not prevent him from seeking to carry out the object at which he aimed. He waited an opportunity. At length, as he vainly fancied, it presented itself. Instigated by princes equally ambitious and less sagacious and more unscrupulous than he was, the people of India were persuaded that they might successfully rise against their English rulers, who had brought them out of a state of anarchy and constant warfare and misery, and had established peace and prosperity in their country. Their ignorance and gross superstition made them the facile tools of their designing chiefs. In 1857 the great sepoy revolt broke out. Prince Dakkar, under the belief that he should thereby have the opportunity of attaining the object of his long-cherished ambition, was easily drawn into it. He forthwith devoted his talents and wealth to the service of this cause. He aided it in person; he fought in the front ranks; he risked his life equally with the humblest of the wretched and misguided fanatics; he was ten times wounded in twenty engagements, seeking death but finding it not, but at length the sanguinary rebels were utterly defeated, and the atrocious mutiny was brought to an end. Never before had the British power in India been exposed to such danger, and if, as they had hoped, the sepoys had received assistance from without, the influence and supremacy in Asia of the United Kingdom would have been a thing of the past. The name of Prince Dakkar was at that time well known. He had fought openly and without concealment. A price was set upon his head, but he managed to escape from his pursuers. Civilization never recedes; the law of necessity ever forces it onwards. The sepoys were vanquished, and the land of the rajahs of old fell again under the rule of England. Prince Dakkar, unable to find that death he courted, returned to the mountain fastnesses of Bundelkund. There, alone in the world, overcome by disappointment at the destruction of all his vain hopes, a prey to profound disgust for all human beings, filled with hatred of the civilized world, he realized the wreck of his fortune, assembled some score of his most faithful companions, and one day disappeared, leaving no trace behind. Where, then, did he seek that liberty denied him upon the inhabited earth? Under the waves, in the depths of the ocean, where none could follow. The warrior became the man of science. Upon a deserted island of the Pacific he established his dockyard, and there a submarine vessel was constructed from his designs. By methods which will at some future day be revealed he had rendered subservient the illimitable forces of electricity, which, extracted from inexhaustible sources, was employed for all the requirements of his floating equipage, as a moving, lighting, and heating agent. The sea, with its countless treasures, its myriads of fish, its numberless wrecks, its enormous mammalia, and not only all that nature supplied, but also all that man had lost in its depths, sufficed for every want of the prince and his crew--and thus was his most ardent desire accomplished, never again to hold communication with the earth. He named his submarine vessel the "Nautilus," called himself simply Captain Nemo, and disappeared beneath the seas.